GLOSSARY FOR INVERTEBRATE CONFUSION This glossary, to be used with the 4th edition of "Invertebrate Zoology" by R. D. Barnes (1980, W. B. Saunders Co.), was compiled as a labor of love to fill what seemed to a former student to be a considerable gap in the chain of information from text to reader. It makes no pretense to include every scientific term. Those which are in common use as well as obvious ones, i.e. circum pharyngeal, dorso- or ventro lateral, were deliberately omitted. It is hoped that it will clarify or ease the path to the understanding of the vocabulary of invertebrate study. Irving Leving
PREFIXES AND SUFFIXES L., Latin; G., Greek a, ab a, an acanth actin ad alveol amphoape, apoarcheoathrobi-, bioblastbrachibrachybranchibucccalie- (x) capitcaudcephalcerccenochaetchoan-chord chromcoelctencutis(L) (G) (G) (G) (L) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (L) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (L) away, from not, without thorn, spine a ray toward, near pit both, double away from beginning, first in time joint life bud, sprout arm short fin, feather the cheek cup head tait head tail new, recent hair funnel, tube gut, string color hollow comb skin
cytodedentdermde-uterodiduct e, ex ectendenterep(i)eu, ev-eury fer fil gaster glob glom, glomer gnash gul gymn gyr haem hal hemihetero histhalhomohypohyperin is-, isolecithlophlumen macr (o) mela mere meso mete
(G) (L) (L) (G) (G) (G) (L) (L) (G) (G) (G) (G) (G) (G) (G) (L) (G) (L) (L) (G) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (L)
hollow, cell, vessel down, away from tooth skin second double, two a leading, conducting out, without, from outside within bowel on, upon, over good, true broad carrier of thread belly ball ball of yarn jaw throat naked round, circle blood the sea half other, different web, tissue whole, entire alike under above, beyond in, into, not, without (G) similar, equal yolk ridge, crest light large black a part of middle next to
(G) (G) (L) (G) (G) (G) (G) (G)
mio micr (o) mon (o) morph nect neo not (o) odont oligo omm opercul opisth orthpaleo par (a) pectinate peri phag phil phor phot phyl pinaco platy plio pod poly poro post prim (o) pro prove proto pseud (o) pulmo pygram retro rhin rhinch sarc scler som (e) squam steg sten stom (a) styl (e)
(G) (G) (G) (G) (G) (G) (G) (G) (G) (L) (L) (G) (G) (G) (G) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (L) (L) (G) (G) (G) (G) (G) (G) (L) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G)
less small one, single shape
new, recent the back tooth few all cover, lid behind straight ancient beside comb-like, having tooth-like projections around, near to eat loving, friend to bear light tribe board, tablet broad more foot many hole, passage after, behind first before, in front of forward, in front early false lung rump branch backwards nose beak, snout flesh hard body scale roof narrow, straight mouth pillar, column
sub super syn, sym tele teleo tetr thee therm (o) trem tri trich trop troph vas ventr zoe (ie) zyg
(L) (L) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (G) (L) (L) (G) (G)
under, below above, over together far perfect, entire four case, container heat a hole three hair a change, a turn a feeding, one who feeds vessel belly life yolk, a coupling, linkage
VOCABULARY A Acanthocephala(G. akantha, thorn + kephale, head). A phylem of parasitic worm-like pseudo coelomates. Acanthor (der. see above). Larval form of above. Acoelomate (G. a, without + coel, hollow). Animals which lack a body cavity and a solid type of body construction. Acontium (G. Aconto, spear, javelin). In polyps, a mesenterial filament which projects into the gastrovascular cavity and produces enzymes for digestion of food. Acron (G. akron, top, summit, peak). The unsegmented head (prostomium) of annelids. Actinula (G. acting, rod, beam). A larval form of hydroids Aerobe (G. aero, air + bios, life). An organism which requires air or oxygen for life. Aesthetes (G. aisthetikos, sensitive, perceptive). In chitons, mantle cells lodged in the tegmentum which act as sensory organs. Ambulacral area (L. ambulacrum, walk). Five sections of the oral area of echinoderms which contain podia. Ambulacral grove. A furrow extending from the mouth of echinoderms; in a sterodia along each arm.
Amictic (G. a, not + mixtos, mixed). A thin-shelled diploid egg which cannot be fertilized and develops by parthogenesis into an amictic female. Amphid (G. amphi, around, double). An inervated invagination of cuticle in nematodes. Ampulla (L. flask, bottle). Bulb at end of lateral canal in astroida. Anabiosis (G. + bios, life). Inactivity accompanied by water loss and very low metabolic rate. Also cryptobiosis (G. Kryptos, hidden, concealed + bios, life). Anaerobe (G. an, not + bios, life). An organism which cannot exist in the presence of air or oxygen. Anastomose (G. anastomosis, new outlet, new network). Connection between two vessels or hollow organs. Annulus (L. annulus, ring). A spiraled transverse groove of dinoflagelates. If a simple ring, it is termed a girdle. Apodeme (G. apo, from, off, away + demas, body). Projection of procuticle of exoskeleton muscle attachment in crustaceans. Aposematic (G. apo, from, off, away + sema, sign, token). Warning coloration. Archenteron (G. archea, beginning, first cause + enteron, intestine). Pouch formed by invagination of blastula to form primitive gut. Archeocytes (G. arche, beginning + cyte, cell, hollow place). Phagocytic cells found in the mesohyl of spongia. Articular membrane (L. articulus, joint). A thin, chitinous membrane joining segments of the arthropod body. Ascus (G. asco, bladder, bag). A space under the frontal plate which provides, with muscles, the means of protruding the lophophore of bryozoans. Atrium (L. vestibule, hall). The interior cavity of asconoid sponges. Autogamy (G. autos, self + gamete, husband, wife). Self mixing of genetic material within the individual. Autotomy (G. autos, self + temno, cut). The act of casting off an appendage. Autozooid (G. autos, self + zoe, life). An individual feeding bryozoan. Avicularium (ia, pl.) (G. avis, bind). A heterozoid in the form of a pincers or jaw which serve to protect the organism. B Basopodite (G. basis, pedistal, foundation + pod, foot). A/crustacean appendage process attached to the coxapodite and which bears the endo- and exopodites.
Bdelloid (G. bdelo, leech + oid, like, having the appearance of).A class of fresh water rotifers. Benthic (G. benthos, deep). Bottom dwelling organisms. Biramous (L. bi, two + ramus, branch). Two branched; Sometimes extended to cover more than two. Blastula (G. blastos, germ, bud, sprout). The early developmental stage of a metazoan; a spherical layer of cells enclosing a central cavity. Blastomere (G. blastos, germ, bud, sprout + mere. a part). A cell produced during cleavage of an ovum; a blastula cell. Blastozoid (G. blastos, germ, bud, sprout + zoe, life). A reproductive bud of tunicates. Book gills. Leaf like lamellae of Limulus which serve as organs of gaseous exchange i.e. gills. Brachiole (G. brachion, arm). A slender pinnule-like projection which contains the peripheral end of the food groove of fossil crinoids. Buccal (L. bucca, cheek, cavity). A cavity just within the mouth opening . Budding - See fission. C Calyx (G. Kalyx, cup, cover). The body, as differentiated from the stalk, of an ectoproct; the skeletal cup within which a polyp is fixed (scleractinian corals). Capitulum (L. capitalis, relating to the head). In stalked Cirripedia, the main body, excluding the stalk). Carapace (Sp. carapach(o), shield). A chitinous exterior structure covering the crustacean thorax minimally and sometimes the whole body. Cecum, caecum (L. caecum, blind). A pouch or sac within the body which has only one opening. Centrolecithal (G. Kentron, mid point + lecitho, yolk). An ovum in which the nucleus is surrounded by a small amount of nonyolk cytoplasm within a large yolk mass. Cephalon (G. cephalo, head). The interior body of trilobites. Cerata (G. Keratos, horn). Dorsal body projections of nudibranchs. Cercaria (New Latin). The fourth developmental stage of trematodes i.e. a free-swimming tailed tadpole-like form. Chelicerae (G. chele, claw) . Claw-like feeding appendages of chelicerates (eg. horseshoe crabs).
Coanocyte (G. coane, funnel + cyto, cell). Spongia cells which are flagellated and collared which create water currents and extract food from them. Chloragogen (G. ehlor, green + agogue, stimulating). A substance in cells which serves as a center for glycogen and fat synthesis in oligochaetes. Chromatophores (G. chrom, color + phore, bearer). Pigment cells in cephalopods. Cilium, pl. cilia (L. eyelash, hair). A hair-like projection of the cell wall used for locomotion or current generation. Cirri (L. cirrus, curl, tendril) 1. In crinoids, small, jointed appendages attached of the stalk. 2. In Cirripedia, thoracic feeding appendages. 3. In Ciliata, ciliary tufts used for locomotion. 4. In polychaetes, a sensory appendage. 5 . In trematodes and neohabdocoels, an eversible copulatory organ. Clavules (L. clavus, nail). Specialized spines of Echinoideae. They are believed to produce mucus for burrow maintenance and to create water currents. Clitellum (L. clitella, pack saddle). A glandular segment of oligochaetes and hirudinates which forms a reproductive cocoon. Cnidosac (G. Knide, nettle + sakkos, bag). Structures at the tip of cerata of nudibranchs which contain nematocysts. Cnidocil (G. Knide, nettle + cdl, deriv. unknown). A short bristle-like process on the end of the cnidocyte which triggers the discharge of nematocysts. Cnidocyte (G. Knide, nettle + cytos, cell). Cells which contain stinging structures (nematocysts). Coanenchyme (G. coeno, common + chymos, juice). In octocorallians, a mass of mesoglea which has gastrodermal tubes connected to adjacent polyps. Colloblasts (G. collo, glue + blastos, ball). In ctenophores, cells which have adhesive properties and which are analagous to nematocysts. Columella (L. dim. columella, pillar). Central column of the shell of gastropods. Commissure (L. committere, to bring together). A band of fibers joining symmetrical parts, especially in the brain. Condyle (L. condylus, knuckle, knob, enlarged end of a bone). A cuticular knob which engages a socket and permits movement between body segments of arthropods. Conjugant (L. con, with + jugum, yoke, pair). Fused ciliates. Contractile vacuole. Water balancing organelle.
Coracidium (G. Korak raven, deriv?)1. Early larval stage of turbullarians. 2. Also an onchosphere. Coxa (L. hip). The basal section of the leg of chilicerates and insects. Coxal gland (L. coxa, hip). Thin walled sacs which serve as excretory organs of chilicerates. Coxapodite (L. coxa, hip + G. pod, foot). The crustacean appendage process nearest the body, to which the basopodite is attached. Crown (L. crone, crown, wreath). The pentamerous body of a crinoid. Cyclomorphosis (G. cyclo, circle + Morpho, shape, form). A seasonal change in body shape or proportion. Cyclosis (G. cyclo, circle). Streaming protoplasm in amoba. Cysticercus (G. cyst), bladder + New Latin, cercaria, tadpolelike). The second stage of development of cestodes; pre-adult stage. Cytoplasm (G. cyto, cell + plasma, substance). The material contained within the cell wall. Cytostome (G. cyto, cell + stom, mouth). Mouth or oral chamber of ciliates. Cytopyge (G. cyto, cell + pygo, rump, buttocks). Anal opening in ciliates. D Dactylozooid (G. dactylo, finger + zoe, life). Specialized defensive polyp in hydrozoans. Demibranch (L. dimidius, half + branchos, gill). One of a pair of lamelli branch gills.
Deutocerebrum (G. deutos - double + L. cerebrum, brain). The median region of the brain of arthropods. Digenea (G. di, twice, two + genesis, birth, origin). A parasitic organism whose life cycle involves two or more hosts. Dioecious (G. di, twice, two + oeco, house). An organism which produces either male or female gametes, but not both. Ditaxic (G. di, twice, two + tasso, place arrange). A fine muscular contraction which sweeps across half of the foot of some molluses (gastropods). Diverticula (L. diverticulum, a by-path). In anatomy, a pouch or sac opening out from a tube or cavity. Dorsal lamina (L. dorsum, back + lamina, plate). A projecting ridge of finger-like processes (languets) which run from the pharynx to the esophagus in tunicates.
E Ecdysis (G. ekdysis, escape, molt). The shedding of arthropod skeleton. Ecdisone (G. ekdysis, escape, molt). Hormone which causes ecdysis. Echinoplutens (G. echinos, sea urchin + L. pluteus, shield, parapet). The second and planktonic larral stage of echinoderms. Elytra (G. elytron, shield, husk). Plate-like scales. Ectoplasm (G. ecto, out of + plasm, substance). Outer portion of cytoplasm of cells. Endoplasm (G. endo, within + plasm, substance). Inner portion of cytoplasm of cells. Endopodite (G. endo, within + pod, foot). Appendage process which is attached to basopodite of crustaceans. Endostyle (G. endo, within + stylos, pillar, column). In tunicates, a deep groove which extends the length of the pharyngeal wall which contains mucus secreting cells and flagellae. Entolicithal (G. ento, within + licitho, yolk). An ovum which has the yolk as an integral part of the cytoplasm. Entoproct (G. ento, within + proktos, anus, rectus, tail). Sessile bryozoan-like animals with the mouth and anus within the tentacular crown. Ephyrae (Deriv. unknown). Immature medusae. Epiboly (G. epibole, to place upon, throw). In histology, overriding or surrounding other cells in development. Epicardium (G. epi, on, over, upon + Kardia, heart). In tunicates, a tube which parallels the digestive loop. Epicuticle (G. epi, on over, upon + L. cutis, skin). The exterior portion of the chitinous arthropod skeleton. Epiphytic (G. epi, on, over, upon + phytos, plant). Concerning plants which grow nonparasitically on others. Epipodite (G. epi, on, over, upon + pod, foot). Appendange process which is attached to, or is apart of, the coxapodite of crustaceans. It frequently bears gills. Epistome (G. epi, on, upon, over + stome, mouth). A narrow crescent fold which overhangs the mouth of phoronids. Epitheliomuscular cells (G. epi, on, over, upon + there, nipple; + L. musculus, flesh). In hydra, epithelial cells which have basal extensions connected to each other and which are contractile.
Epitoke (G. epi, on, over, upon + toco, birth, offspring). An annelid reproductive individual adapted for bottom dwelling or pelagic existence. Epitoky (See above). The formation of an epitoke. Epizoic (G. epi, on, upon, over + zoon, animal). An external parasitic form. Esthetases (G. aisthetikos, sensitive, perceptive). Chemoreceptors on the first antennae of copepods. Eukaryote (G. eu, good, well + caryo, nut, kernel). A cell whose nucleus is enclosed within a membrane, a characteristic of all life above the level of bacteria and blue-green algae. Eumellibranch gill (G. eu, good, well + L. lamina, plate + G. branchos, gill, fin). Molluscan gills which have formed solid sheets of tissue. Eutely (G. euteleia, thrift, economy). A condition of some aschelminths in which the body is made up of a constant number of cells for each species. Exopodite (G. exoterikos, external + pod, foot). An appendage process which is attached externally to the basopodite of crustaceans. Exumbrella (L. ex, out of + umbra, shace). The exterior upper surface of a medusa. F Facultative (L. facultas, feasibility, means). Having the ability to live under more than one environmental condition i.e. parasitic or non-parasitic. Fillibranch gills (I.. filix, fern + G. brachos, gill, fin). Molluskan gills in which the individual filaments are more or less separate. Filopodia (L. glum, thread + G. pod, podium. foot). A pointed pseudo-podium. Fission (L. cleft, chink). Formation of daughter cells by division: a. Binary if result is two similar cells b. Budding if result is two dissimilar cells c. Schizogony if result is multiple division Flabellum (L. fan). Spatulate process on last leg of Limulus used to clean gills. Flagella (L. flagellum, small whip, lash). A long slender motile appendage of cells. Funiculus (L. funds, rope, cord). Tissue which connects individual bryozoans through pores and which provides some sort of communication . Flame cell. The protonephridium of turbellarians. See text (Barnes, pages 220, 221 and 222). G Gametamy (G. gametos, wife, husband, spouse). Sexual reproduction
Gametogonia (G. gametos, spouse + gone, seed). Primary gametodytes which are shed into the coelom of polychaetes. Gamete (G. gametos, spouse). Reproductive cell. Gamont (G. gamos, union). A gametocyte which is the precursor to a gamete. (See gamogony). Gamogony (G. gametos, spouse + gonad, seed). The development of gametes. Ganglion (G) A knot or plexus of nerves. Gastrodermis (G. gastro, stomach + derma, skin). Nutritive muscle cells of cnidarians and ctenophores. Gastrovascular cavity (G. gastro, stomach + vas, vessel, pouch). A space or channel for digestion. Gastrozoid (G. gastro, stomach + zoid, life-like). Hydrozoan feeding polyp; food gathering individual in colonial tunicates (trophozoite). Gastrula (G. gastro, stomach). A cup-like early stage of germ layer formation characterized by two layers of cells. Gemmules (G. gemma, bud, eye). A spore-like aggregate of sponge material which winters over and grows into a larva in the spring. Girdle (Anglo-Saxon, gydrdel, belt). In polyplacophorans, the peripheral area of the mantle. Gonophore (G. gone, seed + phore, bearer, carrier). The repro ductive structure of a polyp (See medusa). Gnathobase (G. gnathos, jaw + basis, foundation). Heavily armed processes at base of appendages for grinding food in Limulus. Gnathopods (G. gnathos, jaw + pod, foot). The 2nd and 3rd appendages of amphipods which are modified for prehension. H Hectocotylus (G. hecto, hold + Koides, hollow). A cephalopod arm modified as a reproductive organ. Hemocoel (G. haima, blood + coelo, cavity, cup). In arthropods, a sinus or space filled with blood. Hemocyanin (G. haima, blood + cyano, dark blue). The oxygen carrying component of the blood of arthropods, cephalopods, crustaceans and mollusks. Heterozoid (G. heteros, other, different + zoe, life). A modified bryozoan individual which serves many different functions i.e. stolous, attachment discs, etc. Hologamy (G. holo, entire + gamos, union). Fusion of two individuals, each acting as a gamete.
Holophyte (G. holo, entire + phyto, plant). The form of life able to create nutriments out of water, minerals and lignt. Holozoic (G. holo,entire + zoon, animal). Homologous (G. homologos, agreeing). Corresponding in type of structure and deriving from a common primitive origin. Homology - The state of being homologous. Hydranth (G. hydra, many headed + anthus, flower). The oral end of a polyp. Hydrocaulus (G. hydra, many headed + L. caulis, stalk). The stalk of a polyp. Hydrotheca (G. hydra, many headed + theca, case, container). The continuation of the perisarc of hydroids which encloses the hydranth Hydrorhiza (G. hydra, many headed + rhizo, root). Root-like structure at the base of a polyp. Hypertrophy (G. hyper, very, above + trophe, food, growth). Excessive growth. Hypertonic (G. hyper, very, above + tongs, stretching). A medium with high osmotic pressure. Hypodermis (G. hypo, under, beneath + cerma, skin). In arthropods, the underlying layer of integumentary epithelial cells. Hypostome (G. hypo, under, beneath + stoma, mouth). The mouth of a hydra. Hypotonic (G. hypo, less than, under, beneath + tongs, stretching). A medium with low osmotic pressure. I Instar (L. form, likeness). Stages between growth periods in arthropods. Intralecithial (L. intra, within + G. lecitho, yolk). Superficial cleavage of arthropod eggs. Interstitial (L. interstitium, interstice). Situated between the cellular components of tissue; specifically between the epidermis and epithelio-muscular cells of hydras. Introvert (L. intra, within + versus, turn). The head and anterior part of the body of pogonophorans which can be retracte into the body. Iridocycle (G. irid, rainbow, iris + Kylon, area under the eye). Cells in the chromatophores of cephalopods which reflect light differentially. Isogamy (G. iso, the same + gamete, spouse). The fusion of two gametes with the identical genetic material.
Isomyarian (G. iso, the same + L. mya, a kind of mussel). A primitive lamellibranch in which the adductor muscles are more or less equal. K Kinetosome (G. Kinetico, pertaining to motion + some, body). Organelle to which the base of the cilium or flagellum is attached. L Labial palp (L. labium, lip + G. palpo, touch, feel). Flap-like folds associated with proboseides which act as food sorting stru tures. Labium (L. lip). The lower lip of arthropods. Labrum (L. lip). The lip-like upper prominence of mouth parts of chewing insects. Lamellibranchea (L. lamella, plate + G. branchos, lung). See pelecypod.
Lappets (Mid. Eng. lappe, fold, wrap). Movable plates on ambulacral groove of crinoids, each associated with three podia. Lamellibranchea (L. lamina, plate + G. branchos, gill, fin). Mollusks having 2 valves hinged dorsally and with sheet-like gills having a food gathering function. Symon. bivalves, pelecypods. Lamella (L. lamina, plate). a. Folded filament half of molluskan gill b. Leaf-like folds of gills of chelicerates (book gills). Lanquets (Deriv. unknown). Finger-like processes which run posteriorly to the esophogus of tunicates. Lecithotrophic (G. lee, tho, yolk + trophe, food, nourishment). Developing forms which receive their nourishment from yolk. Lobopodia (G. lobos, a rounded protuberance + pod, foot). A blunt pseudopodium. Locular (L. loculus, cell, box). A chambered body. Lophophore (G. lopho, mane, crest + phore, bearer, carrier). A food capturing organ consisting of ciliated tentacles which are found on phoronids, bryozoans and brachiopods. Lorica (L. lether cuirass or corselet). The shell, test or thickened encasement of bdelloid rotifers. Lumen (L. light, window). In biology, a duct, hollow or enclosed space. Lunules (L. dim. of luna, moon or crescent). Large elongated notches or openings in the body of some echinoderms. Lysosome (G. Blysis, dissolve, break up + some, body). A cellular organelle containing digestive enzymes.
M Madreporite (Deriv. unknown - perhans Spanish madre, mother + G. poros, hole). A modified pore V in the aboral surface of some echinoderms. [which connects to water channels.] Malpighian tubules (Malpighi, Italian anatomist who discovered capillaries + L. tubus, pipe). Slender tubes which carry wastes from the diverticula to the intestine. Mandible (L. mandibula, jaw). Short, heavy mouth parts of crustaceans used for biting and grinding. Mantle-palium a. In bivalves and brachio pods, a sheet of muscular, sensory and secreting tissue lying beneath the valves. b. In cephalopods a muscular structure surrounding the body. c. In barnacles, the enveloping carapace of larval forms. Manubrium (L. handle, haft). A scyphoran structure which hangs from the subumbrella and surrounds the mouth aiding in capture and ingestion of prey. Marsupium (G. marsupion, pouch, bag). In amphipods a brood chamber which holds the eggs. Mastax (G. mouth). The mouth of a rotifer. Mastigophora (G. mastigo, whip + phore, bearer, carrier). Zoo or phytoflagellales which have flagellae. Maxillae (L. jawbones). Pairs of feeding appendages of crustaceans. Maxillipeds (L. jawbone + G. pod, foot). The first three appendages on the thorax of malacostrans which have been modified to manipulate food. Medusa (L. a gorgon). A free swimming bell or umbrella shaped cnidarian. Medusoid (L. a gorgon). In hydra, a free swimming reproductive form which develops into a medusa or is retained as a gonophore. Mesenchyme (G. meso, middle + chymos, juice). Cells which develop into connective tissue, blood and blood vessels. Mesenteron (G. meso, middle + enteron,- intestine). The central part of anthozoan gastrovascular cavity. Mesentery (G. meso, middle + enteron, intestine). A supporting or enfolding membrane which attaches organs to the body wall or other organs. Mesoglea (G. meso, middle, glia, glue). The thick gelatinous material making up the major part of the inner body of medusae. Mesohyl (G. meso, middle + hylister (?), sieve). A gelatinous matrix lying below the pinacoderm in spongia.
Metachronal (G. meta, between, after + chronos, time). Wave-like beating of fields of cilia or flagellae. Metamerism (G. meta, between, implying change + meris, share portion -pernaps indicating change from acoelomate to coelomate body archetecture). Division of body into segments along an amteropostorior axis. Metanephridium (G. meta, between + nephro, kidney). The nephridium in which the preseptal end is an open ciliated funnel. Metazoan (G. meta, between + zoon, animal). A multicellular motile heterophic animal. Mictic egg (G. mictos, mixed). A haploid egg which produces males parthogenically if not fertilized. If fertilized, they become dormant after which they develop into females. Monoecious (G. mono, single + oeco, house).- An individual which produces male and female gametes. Monogenea (G. mono, single + genesis, birth, origin). A parasitic organism having only one form or generation in the life cycle. Monoplacophora (G. mono, single + placo, tablet + Phore, bearer, carrier). A class of mollusks having a single symmetrical shell. Monopodal growth (G. mono, single + pod, foot). In hydrozoans, growth at the distal end of the stalk with lateral branching of secondary polyps. The oldest polyp and its hydranth occupy the tip. Monotaxic (G. mono, single + tasso, arrange, place). A fine muscular contraction which sweeps synchronously across the whole surface of the foot of gastropods. Myogenic (G. myo, muscle + genesis, birth, origin). Muscle contraction which originates and is controlled within the muscle itself. Myonemes (G. myo, muscle + nema, thread). Long contractile fibrils in ciliates. N Nauplius larva (Der. unknown). Earliest larval form of crustaceans - basic crustacean type. Nematocyst (G. nemato, thread + cystos, cell). Toxic stinging structures carried by cnidocysts in hydrozoans and scaphozoans. Nephridium (G. nephro, kidney+ L.ium,quality or nature of). A tubule specialized for excretion and/or osmoregulation. See proto- and metanephridia. Nephrocytes (G. nephro, kidney + cytos, cell). Cells which are capable of filtering and accumulating waste particles. Nephrostome (G. nephro, kidney + stoma, mouth). The fan shaped open and ciliated end of metanephridia in polychaetes.
Neuro pile (G. neuron, nerve + L. pile, column). Intertwined processes of the interior of the ganglion. Neuropodium (G. neuro, nerve + pod, foot+ L. ium,quality of). Lower part of the parapodium. Nudimental gland (L. nudus, nest). A gland of cephalopods (e.g. Loligo) which provides a gelatinous mass which covers the eggs. Notopodium (G. noto, back + pod, foot). The upper part of the parapodium. Nucal organs (Arabic, nukla, nape of neck). Ciliated sensory pits in the head region of polychaetes. Nucleus (L. nucula, dim, kernel). Chromosomes contained within a double membrane, separate from the cytoplasm of the cell. The region of the cell containing the genetic material, separated from the cytoplasm by a double membrane (the nuclear envelope). Nudibranchs (L. nudus, bare + G. branchos, gill, fin). An order of gastropods characterized by a secondarily bilateral symmetry and loss of shell, mantle and original gill. *They are coiled tubes with a short, stiff bristle-like process which is everted for protection or prey capture. O Obligate (L. obligatus, bound) Biol. Restricted to a particular condition of life i.e. parasites which must live in close association with hosts. Odontophore (G. odonto, tooth + phore, carrier, bearer). The cartilaginous base for the radula of mollusks. Onchosphere (G. oncho, hook, barb + L. sphere, ball). The ciliated free-swimming larva of cestodes. Operculum (L. cover, lid). In serpulids, a modified radiole which serves as a plug when the crown is withdrawn. Ophiopluteus (G. ophio, snake + L. pluteus, shed, parapet). The second and planktonic larval stage of ophioroides. Opisthaptor (G. opistho, behind + apo, bind, fit). A muscular organ which attaches a parasite to its host by means of suckers, hooks, etc. Opisthosoma (G. opistho, behind + some, body). The posterior portion of pogonophores. Osculum (L. little mouth). The large opening at the top of the atrium of asconid sponges. Osphradium (G. osphresis, smellable). Sensory areas on the poster margin of efferent gill membranes which have a chemoreceptor function.
Ossicle (L. ossiculum, dim. of ossis, bone). Calcareous rods, crosses or plates which are the skeleton of asteroids. Ostium, Ostia, pl. (L. door). Lateral openings in the heart of arthropods. Also the incurrent pore of sponges. Ovicell (L. ovum, egg + cell). A structure at one end of bryozoans which holds the embryo and serves as a brooding chamber. Ocelli (L. ocellatus, having small eye spots). Light sensitive organs. Ommatidium (G. omma, eye + unknown deriv.). A long cylindrical structure possessing the ability of light reception in the arthropod eye. Oxconformers (G. oxys, sour, acid + E. conform, to adapt). Organisms whose oxygen consumption is regulated in part by the amount available. P Paedogenesis (G. paedo, child + genesis, birth, origin). A sexually mature larval form which does not become adult. Paedomorphosis (G. paedo, child + morph, form + osis, condition of). Reaching sexual maturity with juvenile morphology. In an evolutionary sense. Palium (L. mantle, robe). The epidermis underlying the shell of mollusks. Palium sinus (L. mantle, robe + sinus, space, hollow). A hollow structure below the adductor which is the point of attachment of the siphon of mollusks. Palruella (Deriv. unknown). A stage of development in flagellates characterized by loss of the flagellum and non-motility. Papula (L. pistule, pimple). Outpockets of epithelium of echinoderms which serve, with tube feet, as gas exchange surfaces. Parapodium (G. pare, beside, near + pod, foot). Lateral appendages extending from the segments of annelids and from the body or foot of some mollusks. Parenchyma (G. pare, beside, near + chyma, juice). A spongy mass of cells. Parthenogenesis (G. parthenos, virgin + genesis, birth, origin). Reproduction by the development of an unfertilized egg. Paxilla (L. paxillus, nail, peg). Ossicles on the aboral surface of asteroids raised above the surface and crowned with small spines. Pecten (L. comb). Comb like chitinous plates which project from the sides of scorpions and which are sensory. Pedicellariae (L. pes, pedis, foot + cellarius, steward). Small specialized jaw like structures of echinoyds which protect, and in one case, capture prey.
Pedicle (G. pea, foot + L. iculus, dim. suffix). A cylindrical extension of the ventral wall of orachiopods which attaches to the substrate. Pedipalp (L. pes, pedis, foot ~ palpo, feel, touch). A sensory appendage arising out of prosoma and modified to perform various functions. Pelecypod (lamellibranch) (G. pelecy, ax, hatchet + pod, foot). A class of mollusks which have two shell valves and a large foot, both laterally compressed, and gills which have assumed a food collecting function. Pelmatazoa (G. pelma, sole of foot). Animals which travel on soles of foot (i.e. gastropods). Pellicle (L. pellis, skin). Body covering of ciliates. Pericardial (G. pert, near, on, around + kardia, heart). The region nearest the heart. Perihemal - spaces or sinuses (G. pert, on, around, near + hema, blood). Separate extensions of the coelam; part of the bloodvascular system of asteroides. Perrostracum (G. pert, on, around, near + ostrakon, shell). The outer layer of the mollusk shell. Peripods (G. peri, on, around, near +pod, foot). Crustacean thoracic appendages. Periproct (G. pert, on, around, near + proctos, anus). The anal region of echinoderms. Perisark (G. pert, on, around, near + sarco, flesh). In hydroids a non-living protein-chitinous envelope which acts as a support. Peristalsis (G. pert, on, around, near + staltikos, contraction). Undulations produced by waves of contraction in the longitudinal muscles of the body wall. Peristome (G. pert, on, around, near + stoma, mouth) 1. Groove which leads to cytostome in protozoans 2. Pre-oral chamber of ciliate 3. First complete segment of annelids 4. Post-oral region of polychaetes. Peristomial membrane (G. pert, on, around, near + stoma, mouth). In ophiuroids a roof-like structure over the prebuccal cavity. Perivisceral (G. pert, on, over, around + L. viscera, entrails). Region nearest the intestines. Petaloid (G. petalon, leaf). In echinoderms the aboral ambulacural area which radiates from the aboral center. Phagocyte (G. phago, to eat + cyte, hollow place, cell). Cells which engulf food particles or foreign bodies. (Phagocytosis; the process of engulfment by a phagocyle)
Phasic neurons (G. phasis, to appear + neuron, nerve). Newrons which initiate fast but brief muscle contractions in arthropods. Pharynx (G. throat). Area between the mouth and nasal passages and the larynx. Phasmid (G. phasma, apparition, specter). Unicellular glands in the tail of nematodes. Phytoflagellate (G. phyto, plant + L. flagellum, whip). Single celled protozoa having flagellae and chloroplasts. Photophores (G. photo, light + phore, bearer). Light producing organs of euphaniaceans-krill. Pinnules (L. pinnula (dim.), feather, wing). Jointed appendages on arms of crinoids giving them a feather-like appearance. Pinocytosis (G. ping, drink + cyto, cell). Uptake of liquid by cellular engulfment. Polyplacophore (G. poly, many + placo, flat, tablet + phore, bearer, carrier). Chitons which have eight overlapping transverse plates as shells. Plankton (G. planeto, wandering, roaming). Floating oceanic organisms. Planospiral (L. planus, flat, even + spiralis, coil, twist). A spiral form which extends more or less horizontally. Planula (L. planus, flat, even). Ciliated free swimming larva of coelenteratis. Pleopod (G. pleo, swim, sail + pod, foot). Interior abdominal appendages used for swimming, ventilation, food/gathering, etc. in malacostricans. Plicate gill (L. plicatus, folded). A molluscan gill which the surface of the lamellae has been increased by folding along the long axis. Pleuron (G. pleura, side). The two lateral cuticular sections of the skeleton of arthropods. Podium (L. platform, projection). Tubular projections on the ambulacural groove of asteroids which serve as locomotor organs. Polyp (G. polypous, coral). A sessile cnidarian. Polypoid (G. polypous, coral + eidos, having the form of). Resembling a polyp, a sessile cnidarian. Pneumostome (G. pneumo, wind, air, breath + stoma, mouth). Porelike opening in pulmonate snails leading into lung or mantle cavity. Podium (podia, pi.) (G. pod, foot). Tubular projections on the arms of echinoderms which serve as locomotor organs.
Polian vessicles (Deriv. unknown). Elongated muscular sacs suspended in the coelom of some asteroids which are believed to serve as expansion chambers of the water vascular system. Polychaete (G. poly, many + chaeto, long hair, mane). A class of annelids with paired lateral fleshy appendages (parapodia). Polyp (G. polypos, many footed). Coelanterate individual e.g. coral, anemone. Polyplucophora (G. poly, many + placo, tablet + phores, body). A class of mollusks having a body covering of transverse overlapping plates. Polyploid (G. poly, many + ploid - der. unknown). Having more than two complete sets of chromosomes. Post larva (L. post, after). The last stage in the development of crustacean larvae. Pre-epodite (L. pre, before + G. epi, around, on, near + pod, foot). Outer gill bearing structure of the appendage of trilobites. Proboscis (G,. proboskis, snout). An extensible or extended structure containing sense organs or mouth and feeding aparatus. Proboscides (G. pro, in front of + boske, food, fodder). Tentacles on the margin of the mouth of protobranchia. Proctodeal (G. proctos, anus, tail). The hind gut region of arthropods. Protocuticle (G. pro, in front of + L. cutis, skin). The layer of cuticle lying immediately under the epicuticle in arthropods. Proglottid (G. pro, in front of + glottis, mouth of the windpipe). Linearly arranged individual reproductive segments of the strobila of cestodes. Prokaryote (G. pro, in front of + caryo, kernel, nut). A one celled organism whose genetic material is distributed throughout the cell. Includes bacteria and blue-green algae. Propodium (G. pro, in front of + pod, foot). The fore part of a podium. Prosobranch (G. prove, forward + branchos, gill). Primitive mollusks of the sub order Archeogastropods. Prosoplyle (G. prove, forward + pyre, gate, orifice). Pores opening into the incurrent canals of syconoid sponges. Protocereberum (G. proto, first + L. cerebrum, brain). The anterior portion of the brain of arthropods - see prefixes deutero - and trito. Protonephridium (G. proto, first + nephro, kidney). Primitive excretory and osmoregulatory organ. See text (Barnes) for flame cells.
Protoplasm (G. proto, first + plasma, substance, that which is formed). All cellular material. Protopodite (G. proto, first + pod, foot). The two most proximate elements of the crustacean biramous appendage. Protostyle (G. proto, first + style, pillar, colemn). A rotating mass of mucus in the stomach of molluscs. Prototroch (G. proto, first + trocho, ball, round). Free swimming larvae of mollusks characterized by a girdle of ciliated cells. Protozoan (G. proto, first + zoon, animal). A single celled animal. Pseudo branch (G. pseudo, false + branchos, gill). In aquatic pulmonates a gill formed secondarily from folds of the mantle. Pseudofeces (G. pseudo, false + L. feces, dregs, rejected material). Material too large to be digested and egested by bivalves. Pseudopodia (G. pseudo, false + pod, foot). A flowing extension of the body of sarcodinians. Pteropods (G. ptero, feather, wing + pod, foot). An order of swimming pelagic opisthobranchs. Pygidium (G. pygo, rump, tail). The terminal end of annelid worms. R Radioles (L. radium, rod, spike). A bipinnate feeding organ of fanworms which forms a conduit for transporting food particles to the mouth. Radule (L. radula, scraper). In mollusks, a feeding organ consisting of rows of chitinous teeth. Redia (Deriv. unknown). The third developmental stage in the trematode life-cycle. Rhabdites (G. rhabdo, stick, rod + ite, having the nature of). In turbellarians, rod shaped epidermal bodies. Rhabdomere (G. rhabdo, stick, rod + mere, part, portion). The area of retinular cells oriented at right angles to the axis of the omatidium of arthropods. Reticupodia (L. reticulatus, net-like + pod, foot). Branched interconnected thread-like pseudopodia. Retinula (L. rete, net). A network of rhabdomes which line the omatidium of arthropods. Rhabdome (G. rhabdos, rod, staff). An enclosed central space, lined with rhabdomeres, in the eye of arthropods. Rhmophore (G. rhino, nose + phore, bearer, carrier). Modified opisthobranch tentacle containing tactile and chemoreceptor cells.
Rhopalium (G. rhopalon, club). Concentrations of neurons in the margins of scyphozoans. S Saccules (L. sacculus, dim of saccus, bag). Small spherical bodies near the outer sides of lappets in crinoids. Saprophyte (G. sapro, rotten + phyto, plant). A plant which obtains its nutrients from dead organic material. Saprozoic (G. sapro, rotten + zoon, life). An organism which obtains its nutrients from dead organic material. Sarcodinas (G. sarco, flesh). Protozoans having flowing extensions of the body i.e. pseudo podia. Scalid (L. scale, stair, ladder). Longitudinal rib like conical projections on the introvert of priapulids. Schizogamy (G. schistos, split + gamos, union). See fission. Scolex (G. scolo, thorn, pointed). The anterior region of the head of cestodes. Scaphognathite (G. scapho, trough, hollow vessel + gnathos, jaw). A paddle-like structure which produces an inhalent current which flows over the lamellae of malacostrians. Scyphistome (G. scyphus, cup + stoma, mouth). In schyphozoans, the polyploid larva, similar in appearance to a hydra, which develops from a planula. Scyphozoan (G. scyphus, cup). The cnidarians in which the medusa is the dominant and conspicious individual in the life cycle. Seminal vessicle (L. semen, seed). A coelomic pouch which provides for maturation of gametes of oligochaetes. Septibranch (L. septum, fence, wall + G. branchos, gill). A subclass of mollusks having degenerate gills modified to muscular septa. Seta, pl. setae (L. seta, bristle). A modified ennervated cilium. Sinus (L. cavity, recess). Any cavity, recess, or passage in tissue or bone. Siphonoglyph (G. syphon, pipe, tube + glypho, carve, engrave). In anemones, a ciliated groove at each end of the mouth which provides for circulation of water. Solenogaster (G. soleno, a pipe + gaster, stomach). A class of worms-shaped mollusks. Spermatheca (G. spermation, seed + theca, case, container). Chambers or receptacles for storage of sperm. Spermatophore (G. spermation, seed + phore, carrier, bearer) Sperm contained within a membrane or case.
Spheridia (L. sphere, ball). Statocyst containing structures in echinoids (urchins, sand dollars). Spicule (L. kernel of grain, point). Skeletal process of spongia,either calcareous or siliceous. Sporocyst (G. spore, seed + cyst, cell). The second developmental phase of a trematode lifecycle, a hollow structure which develops into a radia. Sporogony (G. spore, seed + gony, node). The development of spores Sporozoite (New L. spore, seed + zoa, life). Stage in life-cycle of some protozoans, the development of which follows sporogony. Statoblast (G. statos, fixed, placed + blastos, ball). Resistant reproductive bodies of bryozoans which germinate under favorable conditions. Statocyst (G. statos, fixed, placed + cyst, cell). Kinetic sense organs; chambers containing statoliths (concretions) in contact with recptor cells. Sternum (G. sternon, breast, chest). The ventral cuticular skeleton of arthropods. Sterogastrula (G. stereos, solid, first, hard + gaster, belly, paunch, womb). A blastula changed to a solid gastrula by ingression, a process by which cells move into the blastocoel. Stigmata (G. stigma, mark, spot). Pharyngeal slits in tunicates. Stolon (L. stolo, branch, shoot, runner) - Runner connecting hydroids in colonial cnidarians. Stomodeal (G. stoma, mouth). The foregut region of arthropods. Stomodium (G. stoma, mouth + ium). Mouth area of larvae and gastrulae. Strobila (G. strobilos, twisted or turning). 1. Posterior body of cestodes consisting of linearly arranged proglettids. 2. The polyploid stage of scyhozoans which produce medusae by transverse budding. Style sac (G. style, pillar, column). The posterior conical section of the stomach of molluscs. Subumbrella (L. sub, under + umbra, shade). Lower exterior surface of medusae. Superposition image (L. super, over f positus, placed, put). The response of a rhabdomere to light entering from adjacent ones. Synapse (G. synapsia, connection, junction). Connections between neurons. T Torsion (Mid. Eng. torcion, to twist). In mollusks, the visceral mass, mantle and mantle cavity being twisted 180degrees counterclock wise.
Totipotent (L. totus, all + noteus, powerful). Cells which can be transformed into all other types i.e. archeocytes. (Undifferentiated cells) Trachea (L. windpipe). Respiratory tubes of insects and some arachnids. Trichobothria (G. tricho, hair + bothros, trench, pit). Long sensitive hairs, set in a socket; the most important sense organs of arachnids. Trichocyst (G. tricho, hair + cyst, cell). Organelles containing fluid hardens into rod-like structures for defense or attachment. Tritocerebrum (G. tritos, third + L. brain). The posterior region of the arthropod brain Trivium (L. tri, three + rivus, alive). The three ventral ambulacral areas of holothuroids. Trophozooid (G. trephin, nourish + zoe, life). A feeding or nutritive polyp (gastrozooid). Tun (L. tunica, garment, husk). An animal which has undergone anabiosis. Tunicin (L. tunica, garment, husk). A type of cellulose which is the principal constituent of the covering of tunicates. U Umbo (L. boss, knob). A dorsal projection of the valve of bivalves. V Vacuole (L. vacuus, em~ty). A liquid-filled cavity in a cell. Vector tissue (L. carrier, messenger). Special tissue which acts as a passageway for sperm moving to ovisacs in hirudineans. Vibraculum (L. vibrissa, whisker, hair). Modified bryozoan operculum with a seta used to sweep away detritus. Veliger larva (Deriv. unknown). Molluscan larva in which the foot and shell make their appearance. Velum (L. curtain, veil). Marginal flap or shelf attached to subumbrella at margin of bell of medusae. Vitillarium (L. vitellus, yolk of egg +arium, place or thing connected with). A structure in the flatworm ovary which produces yolk eggs. Zoea (G. zoe, life). The second stage of crustacean larvae. Zooecium (G. zoe, life +L. ium, nature of). The external covering of bryozoans. Zoochlorellae (G. zoe., life +chloro, green). Photosynthetic cells which live commensally with cnidarians and ctenophores.
Zooid (G. zoon, animal +id, nature of). 1. Individual organisms which are attached in a chain-like fashion to form a colony. 2. An individual bryozoan. Zooflagellates (G. zoon., animal +flagellum, whip). Protozoans which have one or more flagellae and are without chloroplasts. Zooxanthellae (G. zoon, animals + xanthos, yellow). 1. Symbiotic dinoflagellates 2. Foreign animals living symbiotically with marine animals. Zygote (G. zygon, yoke, pair). A cell created by union of two gametes; a diploid form of a reproductive cell. Zygosis (G. zygon, yoke, pair). The process of the union of two zygotes.