University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln

Armand R. Maggenti Online Dictionary of Invertebrate Zoology Parasitology, Harold W. Manter Laboratory of

September 2005

Online Dictionary of Invertebrate Zoology: O

Mary Ann Basinger Maggenti University of California-Davis

Armand R. Maggenti University of California, Davis

Scott Gardner [email protected]

Follow this and additional works at: https://digitalcommons.unl.edu/onlinedictinvertzoology

Part of the Zoology Commons

Maggenti, Mary Ann Basinger; Maggenti, Armand R.; and Gardner, Scott, "Online Dictionary of Invertebrate Zoology: O" (2005). Armand R. Maggenti Online Dictionary of Invertebrate Zoology. 10. https://digitalcommons.unl.edu/onlinedictinvertzoology/10

This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Armand R. Maggenti Online Dictionary of Invertebrate Zoology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 621 On line Di ctio nar obliterate a. [L. obliteratus,y eorfased] Indistinct. Inv erte O oblong a. [L. oblongus, rather lonbgra] Elliptical; elongated; te Z longer than broad. ool ogy oblong plates (ARTHRO: Insecta) In aculeate Hymenoptera, the innermost or posterior pair of plates immovably fixed obconical a. [L. ob, inverse; conic, cone] Inversely conical; in on each side of the bulb and stylet of the sting. the form of a reversed cone. oblongum n. [L. oblongus, rather long] (ARTHRO: Insecta) In obcordate a. [L. ob, inverse; cor, heart] Inversely heart- Coleoptera wings, a special oblong cell formed when M 1 is shaped. connected with M 2 by means of one or two cross veins. obese a. [L. obesus, fat] Distended; enlarged; corpulent. obovate a. [L. ob, inverse; ovate, -shaped] Inversely egg- obimbricate a. [L. ob, inverse; imbrex, tile] Having regularly shaped with narrower end downward. overlapping scales. see obsite. obpyriform a. [L. ob, inverse; pyrum, pear; forma, shape] In- objective synonym One of two or more names based on the versely pear-shaped. same type. obscure a. [L. obscurus, covered] 1. Dark; dark of color; dim. oblanceolate a. [L. ob, inverse; lanceolatus, spear-like] In- 2. Remote; hidden. 3. Not well defined. versely lanceolate obsite a. [L. obsitus, barred] Refers to a surface covered with oblate a. [L. oblatus, spread out] Flattened; pertaining to a equal scales or other objects. see obimbricate. spheroid of which the diameter is shortened at two oppo- obsolescence n. [L. obsoletus, to wear out] 1. The process of site ends; flattened at the poles. gradual reduction or disappearance of a taxon. 2. A gradual obligate a. [L. obligare, to be required] Pertaining to the in- cessation of a physiological process. ability to live in a different environment. see facultative. obsolete a. [L. obsoletus, to wear out] Obscure; not distinct; obligate parasite A parasite that cannot exist without a host atrophied; imperfectly developed. during all or some portion of the life cycle. see facultative obtect, obtected a. [L. obtectus, covered over] Covered; en- parasite. closed within a hard covering. obligate symbiont An organism that is physiologically de- obtect pupa (ARTHRO: Insecta) A pupa in which the append- pendent upon a symbiotic relationship with another. see ages are glued down to the body by a secretion produced facultative symbiont. at the larval/pupal molt. see exarate pupa. oblique a. [L. ob, inverse; liquis, awry] Slanting; deviating obturaculum n. [L. dim. obturare, to plug or close] (ARTHRO: from the perpendicular, or a particular horizontal direction, Insecta) In Anoplura, a connective-like tissue structure that but not perpendicular to it. divides the hemocoel of the head from the thoracic hemo- oblique muscles 1. (ECHI) Innermost muscle layer of body coel; continuous posteriorly with a heavy coat surrounding wall; may form oblique or nearly transverse fascicles be- the thoracic ganglia; neck-plug. tween bands of the longitudinal muscles. 2. (SIPUN) A thin obturator n. [L. obturare, to plug or close] Any structure that layer of diagonally placed muscle between the circular and closes off a cavity. longitudinal muscles. obtuse a. [L. obtusus, blunt] Blunt or rounded at the extrem- oblique vein (ARTHRO: Insecta) A slanting cross wing vein. ity; not pointed. see acute. 622 623 Maggenti and Gardner On line Di ctio nar obtusilingues n.pl. [L. obtusus, blunt; lingua, tongue] (AR- occipital suture (ARTHRO: Iynosfecta) A transverse suture some- Inv THRO: Insecta) In a former classification, those bees with times present on the back of etrhtee head that separates the bra short tongues having an obtuse or bifid tip. see acutilin- vertex from the occiput dorsally antde Zthe genae from the ool gues. postgenae laterally. ogy obumbrate a. [L. obumbrare, to over-shadow] Overhanging, occipital tentacle see cirrus or partially concealing. occiput n. [L. occiput, back of the head] (ARTHRO: Insecta) 1. obverse a. [L. obvertere, to face] 1. Looking head on. 2. Hav- The dorsal posterior part of the cranium, between the oc- ing the base narrower than apex. 3. Being a counterpart. cipital and postoccipital sutures; in many the boundaries obverse side of colony (BRYO) The frontal side of the colony. with the vertex and postgenae are not delimited. 2. In Formicidae, the short region between the vertex and the obvolvent a. [L. obvolvere, to wrap around] Bending down- neck. occipital a. ward and inward. occludent margin (ARTHRO: Crustacea) In Cirripedia, the occasional species A species sometimes found in a particular margin of the scutum and tergum bordering the orifice. area, but not habitually. occludent teeth (ARTHRO: Crustacea) In Cirripedia, small occipital a. [L. occiput, back of the head] Pertaining to the oc- projections on the occludent scutal margin interdigitating ciput or the back part of the head. with the teeth on the margin of the opposed scutum. occipital arch (ARTHRO: Insecta) The area of the cranium be- occlusion plate (ARTHRO: Insecta) In Heteroptera larvae, a tween the occipital and postoccipital sutures. semicircularly shaped plate located below the lateral pore occipital carina (ARTHRO: Insecta) In Ichneumonidae Hymen- in the ostiole; functioning in scent ejection in any horizon- optera, a subcircular carina on the hind aspect of the head, tal direction. between the vertex and hind margin of the compound eyes occlusor a. [L. occludare, to close] An organ or muscle that and the foramen magnum. closes an opening. occipital cilia see ocular seta occult a. [L. occulere, to hide] Hidden from sight. occipital condyles (ARTHRO: Insecta) A projection on either oceanic zone The open sea beyond the edge of the continental lateral margin of the postocciput with which the cephaliger shelf. of a cervical sclerite articulates; cervical condyle. ocellara (-ae) see ocellus occipital foramen (ARTHRO: Insecta) The posterior opening of the head into the cervix; neck foramen. see foramen ocellar basin (ARTHRO: Insecta) In Hymenoptera, a concave magnum. area, varying in form and size, occupying the median por- tion of the frontal area. occipital ganglion (ARTHRO: Insecta) A single or paired post- cerebral ganglion. ocellar bristles (ARTHRO: Insecta) In Diptera, bristles arising close to the ocelli; in the ocellar triangle. occipitalia n.pl. [L. occiput, back of the head] (GNATHO) An unpaired row of dorsal cilia on the head. ocellar bulb see tentacular bulb occipital margin (ARTHRO: Insecta) In Mallophaga, the poste- ocellar centers (ARTHRO: Insecta) The brain centers of the rior margin of the head. ocelli, found in the outer part of the ocellar pedicels. occipital notch (ARTHRO: Crustacea) In Conchostraca, the ocellar group (ARTHRO: Insecta) In larvae, six angulated indentation at the ear of the cephalon. ocelli on the lateral area of the larval head, dorsal four 624 625 Maggenti and Gardner On line Di ctio nar forming the quadrant of a circle, ventral two farther apart. with the basal segment yooffthe antenna; functioning to pro- Inv tect the eye. erte ocellar pair see ocellar bristles bra te Z ocular emargination (ARTHRO: Insecta) InooMl allophaga, a lat- ocellar pedicels (ARTHRO: Insecta) Long slender nerve stalks ogy connecting the facial ocelli with the protocerebrum. eral emargination of the head in front of the eyes. ocellar plate see ocellar triangle ocular fleck (ARTHRO: Insecta) In Mallophaga, a black spot in the eyes. ocellar triangle (ARTHRO: Insecta) In Diptera, the triangular region bearing the ocelli and often bounded by grooves or ocular fringe (ARTHRO: Insecta) In Mallophaga, small hairs on depressions. the posterior half of the ocular emargination, may extend on the temporal margin. ocellata see apharyngeate cercaria ocularium n.; pl. -ia [L. oculus, eye] (ARTHRO: Insecta) 1. The ocellate a. [L. dim. oculus, eye] Eye-like; spotted; having area around the simple eye or eyes of larvae. 2. In Hymen- ocelli or eye-like spots. optera sawflies, the pigmented area. ocellus n.; pl. ocelli [L. dim. oculus, eye] 1. The simple eyes ocular lobe (ARTHRO: Insecta) On some Coleoptera, a project- or eyespots, occurring singly or in small groups, found in ing thoracic lobe. many invertebrates. 2. (ARTHRO: Crustacea) see nauplius eye. 3. (ARTHRO: Insecta) see stemma, ommata. 4. ocular papilla (ARTHRO: Crustacea) In some Malacostraca, the (MOLL: Polyplacophora) see aesthete. anterior projection on the eyestalk. ochraceous a. [Gr. ochros, yellow brown] Pale yellow; ocular peduncle (ARTHRO: Crustacea) A movable peduncle brownish-yellow. (eyestalk) with a compound eye at the distal end, some- times with two or three segments, sometimes retractable. ochroleucous a. [Gr. ochros, yellow brown; leukos, white] Yellowish; whitish yellow; buff. ocular plates (ECHINOD: Echinoidea) Plates at the terminal end of the ambulacral areas. octactine a. [Gr. okto, eight; aktis, ray] (PORIF) A modified hexactine spicule with 8 rays. ocular sclerites (ARTHRO: Insecta) 1. In some Pseudococci- dae, well developed sclerites extending completely around octamerous a. [Gr. okto, eight; meros, part] (CNID: Anthozoa) each side, each bearing a row of 7 simple eyes near ante- Organs or parts of organs arranged in series of 8. rior margin, plus a single lateral ocellus on each side be- octoploid a. [Gr. okto, eight; aploos, onefold] Cells having 8 hind the mid-lateral member of the anterior row. 2. An an- chromosome sets in the nucleus (8n). nular sclerite surrounding the compound eyes. octopod a. [Gr. okto, eight; pous, foot] Bearing 8 tentacles, ocular seta (ARTHRO: Insecta) In Diptera, one of several setae feet or arms. octopody n. occurring in a line near the posterior margin of each com- octoprostatic a. [Gr. okto, eight; prostates, one who stands pound eye. before] (ANN: Oligochaeta) Having 8 prostates. ocular sinus (MOLL: Cephalopoda) In the Nautilus , an opening octothecal a. [Gr. okto, eight; theke, case] (ANN: Oligochaeta) on the lateral shell margin accommodating the normal arc Having 8 spermathecae. of vision of the eyes. ocular a. [L. oculus, eye] Of or pertaining to the eyes. ocular suture (ARTHRO: Insecta) An annular inflection sur- rounding the compound eyes. ocular bulla (ARTHRO: Crustacea) A knob on the inner surface of the carapace joining the lower and upper orbital margins ocular tube (SIPUN) A tubular depression in the brain contain- ing the pigment of the eyespots or eyes. 626 627 Maggenti and Gardner On line Di ctio nar ocular tubercles (ARTHRO: Insecta) In Hemiptera, supple- oeco- see eco- y of Inv mentary eyes with prominent facets on the posterior area, erte oedaeagus, oedeagus, oedoeagus bsreae aedeagus in addition to the compound eyes. te Z ool oenocytes n.pl. [Gr. oinos, wine; kytos, conotgayiner] (ARTHRO: oculiferous a. [L. oculus, eye; fero, bear] Bearing eyes. Insecta) Large cells in a group on either side of each ab- oculomotor a. [L. oculus, eye; movere, to move] The nerve dominal segment, between the bases of the epidermal cells center of muscle that moves the eye. and basement membrane, or form clusters in the body oculus n.; pl. oculi [L. oculus, eye] The eye; a spot shaped cavity or dispersed and embedded in the body fat; in im- like an eye. matures, associated with molting, and maybe production of lipids in cuticle or synthesis of ecdysone. odona a. [Gr. odous, tooth] Having teeth. oenocytoid n. [Gr. oinos, wine; kytos, container; eidos, form] odonate a. [Gr. odous, tooth] (ARTHRO: Insecta) Of or per- (ARTHRO: Insecta) Round or oval cells, with darkly staining taining to the Odonata. nucleus and clear, uniform, weakly acidophil cytoplasm. odontium n. [Gr. odous, tooth] (NEMATA) The stomatal arma- oeruginous, oeruginus see aeruginous ture generally in the form of a tooth or teeth originating from the anterior stoma (cheilostome). see onchium. oesophagus see esophagus odontoblast n. [Gr. odous, tooth; blastos, bud] (MOLL: Gas- oestrus see estrus tropoda) Cells in the radular sac that secrete the radular official index A list of names or works suppressed or declared teeth. invalid by the ICZN. odontoidea see occipital condyles official list A list of names or works declared to be valid by the odontophore n. [Gr. odous, tooth; phoreus, bearer] 1. (MOLL: ICZN. Gastropoda) The cartilaginous supporting organ of the ogival a. [F. ogive, pointed arch] Bearing the shape of an arch. radula, tongue or lingual ribbon possessing a complicated ogive n. series of lingual teeth; Huxley included the radula. see oikosite n. [Gr. oikos, house; sitos, food] An attached or sta- buccal mass. 2. (NEMATA) A rigid section of the anterior tionary commensal or parasite. alimentary tract from the base of the odontostyle to the beginning of the esophageal musculature, often with olfactory a. [L. olfacere, to smell] Pertaining to the sense of flanges or knobs for muscle attachment. smell; among invertebrates, the organs are variously placed: antennae of and other , tips of odontostyle, odontostylet n. [Gr. odous, tooth; stylos, col- the palpi and legs of spiders, pits on the heads of various umn] (NEMATA: Adenophorea) A stylet derived from an worms, or osphradia of mollusks. olfactibon n. odontium terminating with a dorsally oblique aperture, and originating in the esophageal wall. olfactory cone see sensillum basiconicum odoriferous glands see scent glands olfactory hair see aesthetasc odor trail (ARTHRO: Insecta) A chemical trace laid down by one olfactory lobes (ARTHRO) In the midbrain or deutocerebrum. to be followed by other insects of the same species olfactory papilla (MOLL: Cephalopoda) Papilla found on or nest; the substance is called trail pheromone or trail Teuthoidea, Sepiidae and Vampyromorpha on either side of substance. the head near the neck. oecium, ooecium n. [Gr. oion, egg; oikos, house] (BRYO) An olfactory pits (MOLL: Cephalopoda) In Octopodidae, olfactory ovicell or brood pouch. pits on either side of the head near the neck. 628 629 Maggenti and Gardner On line Di ctio nar olfactory pores see sensillum campaniformium oligotaxy n. [Gr. oligos, fewy;oftaxis, arrangement] Weak devel- Inv opment of secondarily formederotergans (usually not numer- oligogene n. [Gr. oligos, few; genos, descent] A gene deter- bra ous). te Z mining a pronounced phenotypic effect. see polygenes. ool ogy oligogyny n. [Gr. oligos, few; gyne, ] (ARTHRO: Insecta) oligothermic a. [Gr. oligos, few; thermos, heat] Having a tol- Several functional queens in a colony. erance for low temperatures. oligogyral see paucispiral oligotokous a. [Gr. oligos, few; tokos, offspring] Having a small number of young. oligolecithal egg An egg with a small amount of ; isolecithal. see centrolecithal egg, telolecithal egg. oligotrichy n. [Gr. oligos, few; trichos, hair] Few, weakly de- veloped setae. oligolectic a. [Gr. oligos, few; lektos, chosen] (ARTHRO: In- secta) Selecting only a few, as bees collecting pollen from oligotrophic a. [Gr. oligos, few; trophe, food] Pertaining to only a few kinds of flowers; oligotropic. freshwater bodies poor in plant nutrients and unproductive. oligomerous a. [Gr. oligos, few; meros, part] Having fewer oligotropic a. [Gr. oligos, few; tropikos, turning] (ARTHRO: In- parts or organs than other related forms. oligomery n. secta) Visiting only a few kinds of flowers for nectar; oligo- lectic. see monotropic, polytropic. oligonephria a. [Gr. oligos, few; nephros, kidney] Having few excretory tubules. oligoxenous a. [Gr. oligos, few; xenos, host] Said of certain parasites adjusted to live in a limited number of hosts. oli- oligoneura a. [Gr. oligos, few; neuron, nerve] (ARTHRO: In- goxeny n. secta) Having very few wing veins. oligozoic a. [Gr. oligos, few; zoon, ] Having a few spe- Oligoneuroptera, Oligoneoptera see Endopterygota cies or numbers of in a particular habitat. oligophagous a. [Gr. oligos, few; phagein, to eat] Feeding on olivaceous a. [L. oliva, olive] Resembling or having the color only a few species of food plants. see monophagous. of olive green. oligophyletic a. [Gr. oligos, few; phyle, tribe] Derived from a oliviform a. [L. oliva, olive; forma, shape] Oval; resembling an few ancestral forms. see monophyletic. olive in shape. oligopneustic a. [Gr. oligos, few; pneustikos, of breathing] olynthus n. [Gr. olynthus, unripening fig] (PORIF) In calcare- (ARTHRO: Insecta) Having one or two functional spiracles ous forms, a post-settlement stage; in asconoid forms, re- on each side, including the amphipneustic, metapneustic mains as adult form. and propneustic. omega-ramule (ECHINOD: Crinoidea) A branchlet issuing from oligopod n. [Gr. oligos, few; pous, foot] 1. Bearing few legs. 2. the terminal axial of the main-axil. Having fully developed thoracic legs. see polypod, proto- pod. ommata see ommatidium oligopod larva see campodeiform larva ommateum n. [Gr. ommation, little eye] (ARTHRO: Insecta) A compound eye. oligopyrene a. [Gr. oligos, few; pyren, stone of a fruit] With reduced number of functional spermatozoa. see apyrene, ommatidium n.; pl. -ia [Gr. ommation, little eye; idion, dim.] eupyrene. (ARTHRO) One of the component units of a compound eye, consisting essentially of an optical (light gathering) part oligosaprobic a. [Gr. oligos, few; sapros, putrid] Describing a and a sensory part (perceiving and transforming into elec- body of water with slow organic matter decomposition and trical energy); a facet. high oxygen content. 630 631 Maggenti and Gardner On line Di ctio nar ommatochrome see ommochrome Chelicerata) Any extenysioofn of an arthrodial membrane, Inve ommatoid n. [Gr. omma, eye; eidos, form] (ARTHRO: Chelicer- usually in the form of a more ortelebss hyaline intumescence. rate ata) In some Arachnida, a light colored spot on the poste- see Tragardh's organ. Zoo log rior body segment. onisciform larva see platyform larva y ommatophore n. [Gr. omma, eye; pherein, to bear] (MOLL: onomatophore n. [Gr. onoma, name; pherein, to carry] A Gastropoda) A movable process bearing an eye, as in name-bearer; a type. snails; may be fused with the tentacles. ontogeny n. [Gr. on, being; genesis, beginning] The develop- ommochrome, ommatochrome n. [Gr. omma, eye; chroma, ment or course of development of an individual organism color] A group of pigments, products of tryptophane me- from to maturity; as distinguished from that of a tabolism, found in eyes and epidermis of certain inverte- species. ontogenetic a. see phylogeny. brates; it is apparently not involved in the visual process. onychaetes n.pl. [Gr. onyx, claw; chaite, hair] (PORIF) Micro- omnivorous a. [L. omnis, all; vorare, to devour] Capable of scleres with long, thin oxeote spicules, roughened with obtaining nourishment from both animal and plant tissue. spines. omphalian a. [Gr. omphalos, the navel] (ARTHRO: Insecta) onyches see tarsal claws Referring to the orifice (excluding ostiole) of the metatho- onychii see pulvilli racic scent gland of Heteroptera as median and unpaired. omphalium n. see diastomian. onychium n.; pl. -ia [Gr. onyx, claw] (ARTHRO: Insecta) A general term for a pad between the tarsal claws. omphalous a. [Gr. omphalos, the navel] (MOLL: Gastropoda) Having a shell with an umbilicus. Onychophora, onychophorans n.; n.pl. [Gr. onyx, claw; phorein, to carry] A phylum of terrestrial animals com- onchial plate (NEMATA: Adenophorea) In Enoplida, the basal prised of a single class or order of the same name, fre- plate of the onchium. quently referred to as Peripatus ; once considered to be the onchiophore see odontophore missing link between annelids and arthropods, but now onchiostyle see odontostyle considered to be the sister group of the complex of Crustacea, Tracheata, and Chelicerata. onchium n.; pl. onchia [Gr. onkinos, hook] (NEMATA) Stomatal armature, generally in the form of a tooth or ooblast n. [Gr. oion, egg; blastos, bud] A cell from which an teeth originating from the posterior stoma (esophastome). ovum develops. see odontium, esophastome. ooblastema n. [Gr. oion, egg; blastos, bud] A fertilized egg; onchomiracidium n. [Gr. onkinos, hook; merakidion, youth] an oosperm. (PLATY: Trematoda) 1. A term for an in the egg. 2. oocapt n. [Gr. oion, egg; L. captus, capture] (PLATY: Cestoda) The ciliated larva of a monogenetic trematode. A controlling spincter of the that allows mature oo- onchosphere, oncosphere n. [Gr. onkinos, hook; sphaira, cytes to enter the proximal oviduct. ball] (PLATY: Cestoda) The shelled embryo; a hexacanth; oocyst n. [Gr. oion, egg; kystis, pouch] The cystic form in the the first larval stage. parasitic protozoans (Apicomplexa), resulting from sporog- oncogenic a. [Gr. onkos, swelling; gennaein, to produce] Tu- ony; may be hard covered, with a resistant membrane mor causing. (Eimera) or be naked (Plasmodium). oncophysis n. [Gr. onkos, swelling; physis, growth] (ARTHRO: oocytes n.pl. [Gr. oion, egg; kytos, container] An immature female that undergoes meiosis, giving rise to ova 632 633 Maggenti and Gardner On line Di ctio nar or . ponent part of a sting oryoovf ipositor. Inv erte ooecia n.pl.; sing. -ium [Gr. oion, egg; oikos, house] (BRYO: oosperm n. [Gr. oion, egg; sperma, sberaed] A fertilized ovum; a te Z Gymnolaemata) In Cheilostomata, the outer protective part zygote; an ooblastema. ool ogy of an ovicell; sometimes thought to be zooid morphs; a oosphere n. [Gr. oion, egg; sphaira, ball] An unfertilized egg. brood pouch. oostegite n. [Gr. oion, egg; stege, roof] (ARTHRO: Crustacea) ooecial vesicle (BRYO: Gymnolaemata) In Cheilostomata, an In female Peracarida, modified thoracic lamella arising from inner membrane of an ooecium. the coxa of the pereopod that forms a pouch (marsupium) ooeciostome n. [Gr. oion, egg; oikos, house; stoma, mouth] for brooding . (BRYO: Stenolaemata) The gonozooidal orifice, may or may oostegopod n. [Gr. oion, egg; stege, roof; pous, foot] (AR- not have peristome surrounding the aperture of ovicell. THRO: Crustacea) 1. Thoracic limb bearing an oostegite. 2. oogamy n. [Gr. oion, egg; gamos, marriage] The union during An appendage of the genital somite that forms a brood fertilization of a nonmotile female gamete and a motile pouch in some Branchiopoda. male gamete. oogamous a. see , . n.; pl. -cae [Gr. oion, egg; theke, case] (ARTHRO: In- n. [Gr. oion, egg; genesis, beginning] The devel- secta) The covering or case over an egg or egg mass. opment of the female or ovum that takes place in ootid n. [Gr. oion, egg; eidos, form] One of the four meiotic the gonad. products arising in oogenesis. oogenotop n. [Gr. oion, egg; genesis, beginning; topos, place] ootocous a. [Gr. oion, egg; tokos, delivery] Egg laying. (PLATY: Cestoda) A small cellular complex following the ovi- duct within the female where shell ootype n. [Gr. oion, egg; typos, type] (PLATY: Trematoda) A membranes form, enclosing the zygote and several vitelline small chamber of the female duct, surrounded by Mehlis' cells. see columella. glands, where ducts from a seminal receptacle and vitelline reservoir join. oogone see oogonium oozooid n. [Gr. oion, egg; zoon, animal; eidos, form] Any indi- oogonium n.; pl. oogonia [Gr. oion, egg; gonos, offspring] A vidual developed from an egg, not fragmented or budded. germ cell that gives rise to the oocytes by mitotic division. see blastozooid. ookinete n. [Gr. oion, egg; kinetos, move] (ARTHRO: Insecta) opaline a. [L. opalus, opal] Opalescent; bluish or milky white A motile, elongate zygote of a Plasmodium that encysts in with iridescent luster. the stomach wall of a Culicidae. opaque a. [L. opacus, shady] Not transparent or translucent. oolemma see vitelline membrane open cell (ARTHRO: Insecta) A wing cell that extends to the oophagy n. [Gr. oion, egg; phagein, to eat] 1. The eating of wing margin. eggs; egg cannibalism. 2. (ARTHRO: Insecta) In social in- sects, eating its own or nestmate's eggs. open coxal cavity (ARTHRO: Insecta) In Coleoptera, when the coxal cavity is only bridged over by the membrane. oophore n. [Gr. oion, egg; phoreus, carrier] (ANN: Oli- gochaeta) The egg case or capsule. open population A population freely exposed to gene flow. ooplasm n. [Gr. oion, egg; plasma, formed or molded] The opercular membrane (ARTHRO: Crustacea) In Balanomorpha, cytoplasm of an egg. a thin, flexible membrane attaching the opercular valves to the sheath; in Verrucomorpha, a membranous hinge. oopod n. [Gr. oion, egg; pous, foot] (ARTHRO: Insecta) A com- opercular plug or spot (NEMATA) An escape zone or plug by 634 635 Maggenti and Gardner On line Di ctio nar which a larva leaves the egg membrane. opesium n.; pl. -ia [Gr. dyimof. ope, hole] (BRYO: Gymnolae- Inve opercular scar (BRYO: Gymnolaemata) In Cheilostomata, a mata) In Anasca, a large openritnegb below the frontal mem- rate trace of a cuticular operculum in the frontal closure of the brane bordered by the cryptocyst; fuZnocotioning as a pas- log autozooid. sageway for the lophophore in some species.y opercular valves (ARTHRO: Crustacea) In sessile Cirripedia, ophiopluteus n. [Gr. ophis, serpent; pluteus, shed] (ECHINOD: movable plates (2 or 4) occluding the aperture. Ophiuroidea) Brood larva of Phrynophiurida, with arms edged with cilia, that metamorphose into adults after es- operculate a. [L. operculum, lid] Having a lid or operculum. cape from the bursa through the bursal slits or rupture of operculiform a. [L. operculum, lid; forma, shape] Having the the aboral disk. shape of a lid or cover. ophirhabd n. [Gr. ophis, serpent; rhabdos, rod] (PORIF) A operculigenous a. [L. operculum, lid; Gr. gennaein, to pro- megasclere with oxea curved in several places. see euler- duce] Producing an operculum. habd. operculigerous a. [L. operculum, lid; gero, bear] Having an ophiurida n. [Gr. ophis, serpent; oura, tail] (ECHINOD: Ophiur- operculum. oidea) Simple arms with usually lateral, not verticle move- operculum n.; pl. opercula [L. operculum, lid] 1. A lid or flap- ment. like cover. 2. (ANN: Polychaeta) In certain sedentary forms, Ophiuroidea, ophiuroids n.; n.pl. [Gr. ophis, serpent; oura, a modified tentacle that closes the tube; in some Spiror- tail; eidos, form] A Class of Echinodermata, with narrow, bidae ( Pileolaria and Janua ) enlarges and serves as a gradually tapered arms, sharply offset from the central brood pouch. 3. (ARTHRO) a. In Chelicerata, a plate cover- disk, generally 6 or 7 radiate; also called brittle stars, bas- ing the opening of the book-lungs of spiders. b. In Crusta- ket stars and snake stars. cea, scuta and terga and sometimes associated membrane ophthalmic a. [Gr. ophthalmos, eye] Pertaining to the eye. forming the apparatus occluding an aperture. c. In Diplo- poda, a plate-like anterior sclerite of the vulva. d. In In- ophthalmic somite see acron secta, various plates, flaps and specialized structures of the ophthalmocercaria n. [Gr. ophthalmos, eye; kerkos, tail] genital segments. 4. (BRYO) A generally uncalcified mem- (PLATY: Trematoda) A cercaria with eyespots. brane, hinged on its posterior lip that closes the zooidial ophthalmopod n. [Gr. ophthalmos, eye; pous, foot] (ARTHRO: orifice. see mandible. 5. (CNID: Hydrozoa) A cover sealing Crustacea) In Malacostraca, an eye-stalk; a movable pe- the hydrotheca or gonotheca, may be up to four sections; duncle with a terminal eye. the lid on the distal end of a nematocyst. 6. (MOLL) A cor- neous or calcareous structure borne by the foot serving for ophthalmotheca n. [Gr. ophthalmos, eye; theke, case] (AR- closure of the aperture. 7. (PLATY) The lid-like opening of THRO: Insecta) That part of the pupal case that covers the an egg-shell. eyes. opere citato L. Work cited; op. cit.; op. c. opisthaptor n. [Gr. opisthen, behind; haptein, to fasten] (PLATY: Trematoda) In Monogenea, the posterior attach- operon n. [L. opera, work] Adjacent series of nucleiotides that ment organ (sucker or disc). see Baer's disc. codes for messenger RNA molecules. opisthocline a. [Gr. opisthen, behind; clinein, to lean] 1. opesiule n. [Gr. dim. ope, hole] (BRYO: Gymnolaemata) One of Leaning backward. 2. (MOLL: Gastropoda) The growth di- the small notches or pores in a cryptocyst through which rection of a helicocone shell; commonly referring to growth the frontal membrane depressor muscles pass. lines. 636 637 Maggenti and Gardner On line Di ctio nar opisthocyrt a. [Gr. opisthen, behind; kyrtos, curved] 1. body posterior to the leygosf. 2. (POGON) A terminal septate Inve Arched backward. 2. (MOLL: Bivalvia) Referring to sloping in region. see protosoma, metasrotemb a, mesosoma. rate a direction posterior from the hinge axis; used to describe opisthosomatic appendages (ARTHRO: CZhooelicerata) Vestigial log hinge teeth or the slope of the shell. 3. (MOLL: Gastropoda) appendages present on the ventral regionys of segments The growth direction of a helicocone shell; commonly re- VII-XIII, such as genital papillae or valves. ferring to growth lines. opisthosomatic scissure (ARTHRO: Chelicerata) In Acari, a opisthodelphic a. [Gr. opisthen, behind; delphys, womb] narrow band of skin between sclerotized plates; often (NEMATA) Having uteri parallel and posteriorly directed. see transverse on the opisthosoma. amphidelphic, monodelphic, prodelphic, didelphic. opsiblastic a. [Gr. opsios, late; blastos, bud] A delay in cleav- opisthodetic a. [Gr. opisthen, behind; detos, bind] (MOLL: Bi- age, and therefore a prolonged period before hatching; valvia) Said of the ligament that extends posterior to the winter egg. see tachyblastic. umbo (beak). see amphidetic, parivincular. optic a. [Gr. optikos, pertaining to sight] Pertaining to the eye opisthogenesis n. [Gr. opisthen, behind; genesis, beginning] or sense of sight. Development from posterior end of the body forward. optical isomerism Compounds that are mirror images and opisthognathous a. [Gr. opisthen, behind; gnathos, jaw] differ in turning the plane of polarized light left (L-form) or Having mouth parts directed posteriorly. right (D-form). opisthogoneate a. [Gr. opisthen, behind; gonos, seed] Having optic lobes Lateral extensions of the protocerebrum or nerv- the genital opening situated terminally, at the posterior end ous system for innervation of an eye. of the body. see progoneate. opticon n. [Gr. opsis, sight] (ARTHRO: Insecta) The inner zone opisthogonia n. [Gr. opisthen, behind; gonia, corner] (AR- of the optic lobes. THRO: Insecta) The anal angle of the hind wings. optimum a. [L. optimus, best] The most suitable condition for opisthogyrate a. [Gr. opisthen, behind; L. gyratus, revolve] 1. the growth and development of an organism. Curving backwards. 2. (MOLL: Bivalvia) Having the beak pointing posteriorly. orad adv. [L. os, mouth; ad, toward] Toward the mouth. opisthohapter see opisthaptor oral a. [L. os, mouth] Pertaining to or near the mouth. opisthomeres n.pl. [Gr. opisthen, behind; meros, part] (AR- oral arms (CNID: Scyphozoa) In medusae, 4 or 8 often frilly THRO: Insecta) In Dermaptera, the transversely divided oral arms, bearing cnidocytes and aid in the capture and epiproct; the so-called pygidium, metapygidium and telson. ingestion of prey. opisthomerite n. [Gr. opisthen, behind; meros, part] (AR- oral cavity The mouth; the buccal cavity. THRO: Diplopoda) The gonopods of Julida; the posterior oral cone (CNID: Hydrozoa) In polyps, a conical projection part of the modified 9th pair of legs in the male. surrounded by tentacles with the mouth in the center. opisthoparamere n. [Gr. opisthen, behind; para, beside; oral disk (CNID: Anthozoa) In polyps, a flattened area from meros, part] (ARTHRO: Insecta) In Diptera (Cyclorrhaphra), which, usually 8 or multiples of 6, tentacles arise that especially Calyptrata, one of two parameral processes. see communicate with the coelenteron. proparamere. oral hooks see mandibular sclerites opisthosoma n. [Gr. opisthen, behind; soma, body] 1. (AR- oral lappet (MOLL) Basal expansion of labial tentacles; labial THRO: Chelicerata) In Acari or Ixodida, that portion of the veil. 638 639 Maggenti and Gardner On line Di ctio nar oral lobe (CTENO) A muscular lobe on either side of the mouth group; a subdivision ofy aof class or subclass, containing a Inv in Lobata. group of naturally related supeerrftaemilies or families. bra te Z oral plate (ARTHRO: Insecta) The hypopharyngeal floor of the ordinal a. [L. ordin, methodical arrangemeonotl] 1. Belonging or ogy cibarial pump. pertaining to an order. 2. (ARTHRO: Insecta) Crochets of oral segment A ring or segment bearing the mouth. larvae, describing the length or arrangements at the tip. see uniordinal crochets, biordinal crochets, triordinal oral spear see stomatostyle, odontostyle crochets, multiordinal crochets. oral styles (KINOR) Spines arranged in a series around the ordinate a. [L. ordin, methodical arrangement] Arranged in mouth cone. rows, such as ornamentations or punctures. oral surface (ECHINOD: Asteroidea) The entire undersurface of oreillets n.pl. [F. dim. oreille, projection] (ARTHRO: Insecta) the disc and arms. Lateral, spinose processes of male Anisoptera and some oral tentacles (MOLL) Tentacle-like outgrowths of the lip. Zygoptera on the second abdominal tergite, presumed to oral valve (ECHINOD: Crinoidea) One of 5 low triangular flaps act as copulatory aids; auricles. separating the ambulacral grooves. organelle n.; pl. -es, -ae [Gr. dim. organon, instrument] Any oral vibrissae (ARTHRO: Insecta) In certain Diptera, a pair of structure having a specialized function in the cytoplasm of stout bristles or hairs on each side of the face, near or the cell, such as mitochondria, nucleus, plastids, etc. above the oral margin; larger than those on the vibrissal orange rouge (ARTHRO: Insecta) Cells with intracellular tra- ridge. cheoles. orb n. [L. orbis, circle] A circle or globe. orbicular a. organism n. [Gr. organon, instrument] Any individual living orbit n. [L. orbis, circle] 1. (ARTHRO) The part of the head thing. surrounding an eye; orbital fossa. 2. (ARTHRO: Crustacea) organization center see organizer In Decapoda, an opening in the anterior face of the cara- organizer n. [Gr. organon, instrument] The region of an em- pace supporting the ocular peduncle. bryo seeming to control the differentiation and develop- orbital bristles see facio-orbita ment of other cells; organization center; inductor; evoca- orbital carina (ARTHRO: Crustacea) In Decapoda, the narrow tor. region on the margin of the orbit. organ of Bellonci (ARTHRO: Crustacea) Receptors innervated orbital fossa see orbit from the medullae terminales of the brain, consisting of ciliated sensory neurons associated with supporting cells, orbital hiatus (ARTHRO: Crustacea) Gap or slit in the orbital such as glial, bordering and perilemmal cells; has also been margin. called frontal organ, x-organ, rod-shaped organ. see orbital plate see genovertical plate frontal eye complex. orbital region (ARTHRO: Crustacea) That part posterior to the organ of Berlese see mesospermalege eyes bordered by the frontal and antennal regions. organ of Bojanus (MOLL: Bivalvia) A kidney, especially in orbital tooth (ARTHRO: Crustacea) A tooth on the orbital mar- oysters. gin. organ of Hicks see sensillum campaniformium orchitic a. [Gr. orchis, testis] Of or pertaining to testicles. organ of Hoyle see Hoyle's organ order n. [L. ordin, methodical arrangement] A taxonomic 640 641 Maggenti and Gardner On line Di ctio nar organ of Johnston see Johnston's organ which the tentacles protyruodfe. Inv erte organ of Kolliker see Kolliker's organ original description A statement of bcrhaaracters along with the te Z proposal of a name for a new taxon. ool organ of Ribaga see mesospermalege ogy organogenesis n. [Gr. organon, instrument; genesis, begin- orismology n. [Gr. horos, boundary; logos, discourse] The sci- ning] Formation and development of organs in the embryo. ence of defining technical or scientific words of a particular organogenetic a. subject or field of study. organogeny see organogenesis ornamentation n. [L. ornare, to adorn] Sculpturing on the body of an animal or shell. organoid n. [Gr. organon, instrument; eidos, kind] The body forming part of the cytoplasm. ornate cercaria (PLATY: Trematoda) A larval form in the Xiphidiocercaria group, with a tail fin fold; cercariae orna- organoleptic a. [Gr. organon, instrument; lambanein, to take tae. hold of] Capable of receiving a sensory stimulus. orphan nest (ARTHRO: Insecta) In social insects, a nest con- organotroph see heterotroph taining offspring without adults. organs of Tomosvary (ARTHRO) A pair of sensory organs pre- orthocerous condition (ARTHRO: Insecta) In some adult Col- sent on the head at the base of the antennae in Lithobio- eoptera, antennae showing no sign of geniculation, the morpha, Scutigeromorpha and some Insecta, consisting of scape being longer than succeeding segments, and the club a disc with a central pore into which the endings of subcu- loose and three-segmented. see gonatocerous condition. ticular sensory cells converge; temporal organs. orthochromatic a. [Gr. orthos, straight; chromos, color] With organs of Valenciennes (MOLL: Cephalopoda) Paired lamel- normal staining characteristics. lated organs in female nautiloids. orthochromatin n. [Gr. orthos, straight; chromos, color] Sta- orichalceous a. [L. aurum, gold; Gr. chalkos, copper] A color ble chromatin. or luster between gold and brass. orthocline a. [Gr. orthos, straight; clinein, to lean] (MOLL) At Oriental Realm A zoogeographical region including Asia east right angles to the growth direction of the helicocone, es- of the Indus River, south of the Himalayas and the Yang- pecially in oysters; growth lines. tse-kiang watershed, Ceylon, Sumatra, Java and the Philip- pines. orthodont hinge (MOLL: Bivalvia) A hinge in which the teeth approximate the direction of the cardinal margin. orientation n. [L. oriens, the rising sun] Sense of direction; a change in position. orthodromic a. [Gr. orthos, straight; dromos, running] Moving in a normal direction. see antidromic. orifice n. [L. os, mouth; facere, to make] 1. An opening into a cavity; a mouth-like opening. 2. (ARTHRO: Crustacea) In orthogenesis n. [Gr. orthos, straight; genesis, beginning] sessile Cirripedia, the opening in the wall occupied by the Evolution following a predetermined rectilinear pathway, operculum. see aperture. 3. (BRYO) The opening on the independent of natural selection. margin of the orificial wall through which the lophophore orthognathous a. [Gr. orthos, straight; gnathos, jaw] Having passes. straight mouth parts; not projecting. orificial wall (BRYO) 1. In Gymnolaemata, an exterior zooidal orthogyral, orthogyrate a. [Gr. orthos, straight; gyrate, re- wall that bears or defines the orifice through which the lo- volve] (MOLL: Bivalvia) Having the beak point at right an- phophore passes. 2. In Stenolaemata, an orifice through gles to the hinge axis, especially oysters. 642 643 Maggenti and Gardner On line Di ctio nar orthokinesis n. [Gr. orthos, straight; kinesis, movement] A peared have maintainedytohfeir ancestral position. Inv non-directional response in which the speed or frequency of erte os n.; pl. ora [L. os, oris, mouth] Thebmraouth. activity depends on the intensity of stimulation. see kli- te Z ool nokinesis. oscillation n. [L. oscillare, to swing] A singleogsywing from one extreme limit to the other of a sine wave. orthometaneme n. [Gr. orthos, straight; meta, after; nema, thread] (NEMATA) A metaneme parallel to the longitudinal osculant a. [L. osculare, to kiss] 1. Adhering closely. 2. A con- body line; found at the dorsal or ventral border of the lat- necting link between two groups; having intermediate eral epidermal cords. characters, as in genera and species. Orthonectida, orthonectids n.; n.pl. [Gr. orthos, straight; oscular chimney see osculum nekton, swimming] A class of Mesozoa with an asexual osculum, oscule n.; pl. -la [L. dim. os, mouth] 1. (PORIF) A parasitic plasmodial generation in many marine inverte- comparatively large exhalant aperture; an oscular chimney. brates and a sexual free-swimming generation. see apopore. 2. (PLATY: Cestoda) A sucker. orthoneury n. [Gr. orthos, straight; neuron, nerve] (MOLL: osmeterium n.; pl. osmeteria [Gr. osme, odor] (ARTHRO: In- Gastropoda) In forms with bilateral zygoneury, the condi- secta) A fleshy, tubular, eversible pouch usually V or Y- tion of the visceral loop ganglia and crossed connectives shaped, sometimes arising from cephalo- dorso-meson of indicating earlier streptoneury are still evident though the prothorax of Papilionidae caterpillars, that produce a sometimes reduced. see detorsion. penetrating odor; also appearing elsewhere in the bodies of orthoploid see euploid other forms. orthoselection n. [Gr. orthos, straight; L. selectus, select] osmiophilic, osmophilic a. [Gr. osme, smell; philein, to love] Natural selection continuously acting in one direction over a Staining readily with osmic acid. long period of time. osmium see osmosium orthosomatic a. [Gr. orthos, straight; soma, body] Having a osmoconformer n. [Gr. osmos, pushing; cum, with; forma, body in a straight line. shape] An organism having the salt content of the blood orthostasy n. [Gr. orthos, straight; stasis, standing] (ARTHRO: determined by that of the surrounding sea water. Chelicerata) Stage in acarology life-cycle evolution showing osmomorphosis n. [Gr. osmos, pushing; morphos, form] only stases and no stasoids. Change in shape due to osmotic (salt) changes in the en- orthostrophic a. [Gr. orthos, straight; strophe, to turn] (MOLL: vironment. Gastropoda) Coiled in a normal manner, as opposed to hy- osmoreceptors n.pl. [Gr. osmos, pushing; recipere, to re- perstrophic. ceive] Receptors that sense changes in osmotic pressure. orthotaxy n. [Gr. orthos, straight; taxis, arrangement] The osmoregulation n. [Gr. osmos, pushing; L. regulatus, regu- arrangement of similar organs that have ancestral charac- lated] Maintaining the osmotic pressure in the body by ters, and have preserved their normal position. regulating the amount of water and salts, effected by the orthotriaenes a.pl. [Gr. orthos, straight; triaina, trident] (PO- removal of salts, excretory products or water by the ex- RIF) In tetraxons, having clads in the angular form of about cretory organs. 90° with the axis of the rhabdome. osmosis n. [Gr. osmos, pushing] Passage of water through a orthotrichy n. [Gr. orthos, straight; trichos, hair] (ARTHRO: semi-permeable membrane from a solution of lower con- Chelicerata) In acarology, all setae that have not disap- centration to one of higher concentration until the solutions are equal in concentration. 644 645 Maggenti and Gardner On line Di ctio nar osmosium n. [Gr. osmos, pushing] (NEMATA) A structure of sage, usually associatedy wofith a valve or circular muscle. 2. Inve modified intestinal tissue that protrudes into the tissue of (ARTHRO) The paired slitlike opretenbings in the heart. 3. (AR- rate the Demanian organ that is of gonadal origin. THRO: Insecta) In male Lepidoptera, Zthooe opening or area log osmotaxis n. [Gr. osmos, pushing; taxis, arrangement] A re- through which the internal pouch is everted yduring copula- sponse to osmotic pressure change. tion. 4. (MOLL: Bivalvia) One of many tiny holes in the gill walls allowing currents of water through the gills. 5. (PO- osmotic see osmosis RIF) Pore openings entering the interior cavity (the spongo- osmotic pressure Pressure required to prevent the flow of coel or atrium) of sponges; incurrent pores; inhalent pores. solvent through a membrane that has different concentra- ostial a. see ostium bursae. tions of salt on either side. ostium bursae (ARTHRO: Insecta) The copulatory entrance of osphradium n.; pl. -dia [Gr. osphradion, strong smell] (MOLL) the bursa copulatrix in female Lepidoptera, corresponding 1. In Gastropoda, a small sensory organ on the posterior to the vulva of other female insects with the genital open- margin of each afferent gill membrane that functions as a ing on the 8th abdominal segment. chemoreceptor and also determines the amount of sedi- ostium oviductus (ARTHRO: Insecta) In female Lepidoptera, ment in the inhalant current. 2. In Bivalvia, located in the the primary opening of the genitalia through which the exhalant chamber, doubtfully homologous to Gastropods. eggs are laid, situated near the 9th abdominal segment. osseous a. [L. os, ossis, bone] Composed of or resembling ostracum n. [Gr. ostrakon, shell] (MOLL: Bivalvia) 1. The entire bone. calcareous part of the shell. 2. The outer part of the shell ossicle n. [L. dim. os, ossis, bone] 1. A small nodule of chitin secreted at the mantle edge. that resembles bone. 2. (ARTHRO: Crustacea) Teeth and otidium see statocyst tooth-like process in the gastric mill. 3. (ARTHRO: Insecta) For Diptera, see axillary sclerites. 4. (ECHINOD) Plates, otocrypt n. [Gr. ous, ear; kryptos, hidden] (MOLL) An open in- spicules and rods that make up the structure of the endo- vagination of the integument of the foot in certain mol- skeleton. lusks. ossiculum n. [L. dim. os, ossis, bone] 1. An ossicle. 2. (MOLL: otocyst see statocyst Bivalvia) A small calcareous plate reinforcing an internal otolith see statolith ligament; a lithodesma. otoporpae n.pl. [Gr. ous, ear; porpe, pin] 1. (CNID: Hydrozoa) ostia see ostium Lines of cnidoblasts on the exumbrella. 2. (CNID: Scypho- ostiolar peritreme (ARTHRO: Insecta) The ridged, cuticular zoa) Internal tissue tracts on the bell surface above the projections surrounding the ostiole, cresting and being sensory organs at the margin of the jellyfish bell. subdivided into several smaller projections with ridges run- outer coelomic space (BRYO: Stenolaemata) In free-walled ning parallel to the line from each ostiole to the corre- forms, the coelomic space between the outer skeletal wall sponding evaporative cuticle. and the exterior membranous wall. ostiole, ostiola n. [L. ostiolum, little door] 1. Any small open- outer face (MOLL: Gastropoda) In a shell whorl, the surface ing. 2. (ARTHRO: Insecta) In Heteroptera, one of paired between the shoulder and the abapical suture or margin of dorsal abdominal scent gland openings; in adults, located base; same as side of whorl. near the coxa. outer leaf crown see corona radiata ostium n.; pl. ostia [L. ostium, door] 1. Any opening to a pas- outer ligament see lamellar ligament 646 647 Maggenti and Gardner On line Di ctio nar outer lip (MOLL: Gastropoda) Labrum; the outer edge of the overdispersion An ecologyicoafl term referring to nonrandom Inv aperture of a univalve shell extending from the suture to dispersion of individuals in a ehratebitat; as, when a minority bra the foot of the columella. of individual hosts bear the majority toefZparasites. ool ogy outer pigment cells see accessory pigment cells ovicapt n. [L. ovum, egg; captus, capture] (PLATY: Cestoda) A outer plate see quadrate plates sphincter on the oviduct. outer squama see alula ovicell n. [L. ovum, egg; cella, cell] (BRYO) 1. In Gymnolae- mata, marine Cheilostomata with a modified zooecium outer vertical bristles (ARTHRO: Insecta) In Diptera, the more serving as a brood pouch. 2. In Stenolaemata, a gonozo- laterally located of the large bristles on the vertex, and oid; an ooecium. rather behind the upper inner corner of the eye. oviducal gland (MOLL: Cephalopoda) A glandular complex on ova pl. of ovum each oviduct involved in egg coat formation; in some octo- oval a. [L. ovum, egg] Egg-shaped. pods, a storage area. ovarial ligament (ARTHRO: Insecta) A ligamentous strand at- oviduct n. [L. ovum, egg; ducere, to lead] Ducts or passages taching the terminal filaments of an to the dorsal carrying female from the ovary toward the exte- diaphram or body wall, or may be from the opposite side rior; a gonoduct. oviducal a. by way of a median ligament to the ventral wall of the dor- oviferous see ovigerous sal blood vessel; functioning in suspending the developing in the hemocoel. oviform a. [L. ovum, egg; forma, shape] Egg-like in shape. ovarian balls (ACANTHO) In , a central mass found in oviger n. [L. ovum, egg; gerere, to bear] (ARTHRO: Chelicer- the dorsal ligament sac or free in the pseudocoelom from ata) In some Pycnogonida, specialized egg carrying ap- which oogonia are differentiated; free floating ovaries. pendages, as well as functioning in cleaning the long legs and trunk surface. ovarian tube (ARTHRO: Insecta) The tubular part of an ovariole containing the germ cells, oocytes, nurse cells, and follicle ovigerous a. [L. ovum, egg; gerere, to bear] Carrying eggs; cells. oviferous. ovariole n. [L. dim. ovum, egg] (ARTHRO: Insecta) The tubular ovigerous frena (ARTHRO: Crustacea) In Lepadomorpha Cir- division of a female ovary where the oocytes develop. ripedia, a fleshy ridge or lap on the inner surface of the mantle anchoring the egg masses. ovariotestis see ovotestis ovigerous lamella (ARTHRO: Crustacea) In Lepadomorpha ovarium see ovary Cirripedia, the egg masses forming one or more lamellae ovary n. [L. ovum, egg] The female gonad of animals in which within the cavity. see ovigerous frena. the egg cells are developed. ovarial, ovarian a. ovijector n. [L. ovum, egg; jacere, to throw] (NEMATA) A mus- ovate a. (L. ovum, egg] Egg-shaped; oval. cular development of the vagina uterina that aids in the ovately-conic Formed like an egg with a somewhat conic passage of eggs. apex. oviparous a. [L. ovum, egg; parere, to bring forth] Egg-laying. ovate-oblong Between oval and oblong. oviporus n. [L. ovum, egg; porus, passage] (ARTHRO: Insecta) ovate-subquadrate Rounded, but somewhat four-sided. In Lepidoptera, the reproductive opening on segment 9 that serves for the discharge of eggs. ovejector see ovijector 648 649 Maggenti and Gardner On line Di ctio nar oviposit v. [L. ovum, egg; ponere, to place] To lay or deposit oxygnathous a. [Gr. oxys, ysohfarp; gnathos, jaw] Having sharp Inv eggs. jaws. erte bra te Z oviposition n. [L. ovum, egg; ponere, to place] The act of de- oxyphil, oxyphile see oxyphilic ool ogy positing eggs. oxyphilic, oxyphilous a. [Gr. oxys, sharp; philein, to love] 1. ovipositor n. [L. ovum, egg; ponere, to place] Structure on a Tolerant of acid. 2. Staining readily in an acid stain. female animal modified for deposition of eggs. oxyphobe, oxyphobic a. [Gr. oxys, sharp; phobos, fright] Not ovisac n. [L. ovum, egg; saccus, bag] 1. An egg capsule, brood tolerant of acid soils; acidophobic. pouch, or receptacle. 2. (ARTHRO: Crustacea) In female Co- oxytylote n. [Gr. oxys, sharp; tylos, knob] (PORIF) A slender pepoda, the external sac attached to the somite that bears straight sponge spicule, sharp at one end and knobbed at the openings of the gonoducts. 3. (ARTHRO: Insecta) In the other. coccids, the envelope in which eggs are laid; the ovarial cavity in which the eggs are stored. ozadene n. [Gr. ozein, to smell; aden, gland] (ARTHRO: Diplo- poda) A defense gland, secreting a repugnant or poisonous oviscapt, oviscapte n. [L. ovum, egg; captare, to conduct] An chemical. ovipositor. ozopore n. [Gr. ozein, to smell; L. porus, pore] (ARTHRO: Dip- ovivalvula n. [L. ovum, egg; dim. valva, leaf of a folding door] lopoda) The opening of the ozadene. (ARTHRO: Insecta) In female Heteroptera and Ephemerop- tera, a subgenital plate. ovocyte see oocytes ovogonium see oogonium ovoid a. [L. ovum, egg; Gr. eidos, form] Egg-shaped; ovate. ovotestis n.; pl. -testes [L. ovum, egg; testis, testicle] Her- maphroditic reproductive gland; an organ that produces both spermatozoa and ova at the same or at different peri- ods of the life cycle; a syngonic gonad. ovovitellarium n. [L. ovum, egg; vitellus, yolk] (PLATY: Cestoda) A combined mass of ova and vitelline cells. ovoviviparous a. [L. ovum, egg; vivus, alive; parere, to bring forth] Producing eggs that are incubated and hatched within the female's body. see oviparous, viviparous. Copyright ©2005 Armand R. Maggenti and Scott Gardner. ovum n.; pl. ova [L. ovum, egg] The egg cell. oxea n. [Gr. oxys, sharp] (PORIF) A smooth spicule tapering to two similarly pointed ends; amphioxea. oxyaster n. [Gr. oxys, sharp; aster, star] (PORIF) A star- shaped spicule with a small center and pointed rays. oxydiact a. [Gr. oxys, sharp; di-, two; aktis, ray] (PORIF) Having three rays with two fully developed.