Species list




The following glossary provides brief definitions of terms that may be used in this site. Please consult other sources for more comprehensive discussion of the terms. Internal links are provided in the alphabetic table on the left as a convenience to users.


abapical--located at the opposite end of a shell from the apex.

accretion platform--a sandstone bench formed at about sea level by chemical and microbial action (= solution bench)

acteonoidean--a member of the order acteonoidea

aeolid--a member of the suborder aeolidacea, nudibranchs having cerata containing branches of the digestive gland

aeolidiform--resembling an aeolid in body plan.

aglajid--a member of the family aglajidae.

albumen gland--a gland in the reproductive system of mollusks that produces yolk for eggs.

allopatric species--species that do not have overlapping ranges

anal papilla--an elevated structure surrounding the anus

anal siphon--the excurrent tube derived from the mantle that carries wastes away from the animal

anaspidean--a member of the order anaspidea

anus--the opening of the intestine

annulate rhinophores--rhinophores with well defined circular ridges or collars

anterior--toward the front of the animal

antifeedant--a substance that functions as a deterrent to predators

antitropical--species found outside the topics but both north and south of the equator

aperture--the opening or mouth of a shell

apex--the tip of a shell or other structure

apical--toward the tip of a shell or other structure

aplysiid--a member of the family aplysiidae

aplysiomorph--resembling an aplysiid in body form

aposematic coloration--coloration that has evolved as a signal to potential predators that an animal is toxic/distasteful/venomous

arborescent--tree-like in form

arminid--a member of the suborder arminacea

ascloglossan--a member of the order ascoglossa (= sacoglossan)

apical orifice--an opening at the apex of a structure

aposematic--coloration that stands out in contrast to its background, presumably acts as a warning to predators

arcuate--arc-like in shape

auriculate--ear-like in form

autotomize--to drop body parts when disturbed, presumably  as a distraction to predators

azooxanthellate--lacking the symbiotic algae, zooxanthellae

batesian mimicry--when a palatable species closely resembles an unpalatable species

benthic--living on the bottom or floor of the ocean

bifid rhinophores--rhinophores that divide into two branches

bifurcate--splitting into two branches

bilabiate--having two lips or edges

bipinnate--having two series of branches


branchial--having to do with the gills

branchial plume--one gill

branchial sheath--the collar or cup into which the branchia withdraw in dorids

bubble shell--one of many cephalaspideans with thin, inflated shells

buccal mass--the muscular portion of the digestive system between the oral tube and the esophagus

bullomorph--resembling the genus Bulla in body form, resembling a bubble

bulloid--having an inflated shell similar to the genus Bulla

bursa--a pouch or sack

cardiac sack--the sack-like structure that serves as a heart in opisthobranchs

caruncle--the elevated crest between the rhinophores in some arminids

caryophyllidia--tubercles surrounded by spicules that are found on the dorsal surfaces of some dorids

cephalaspidean--a member of the order cephalaspidea

cephalic--pertaining to the head

cephalic hood--an expanded region at the front of the head, particularly in gymnodorids

cephalic shield--the flattened, fleshy plate covering the head  region in cephalaspideans

cephalic tentacles--the most anterior tentacles projecting from the head

ceras (plural:  cerata)--an elongate projection from the dorsal surfaces of aeolids, dendronotids, arminaceans and  sacoglossans, sometimes applied only to those of aeolids

ceratal group--a cluster of cerata

ceratal insertion--the point at which cerata attach to the animal

chitin--a hard protein that forms the jaws, radular teeth and other structures in opisthobranchs

chloroplasts--photosynthetic organelles in the cells of alga and other plants that contain the pigment chlorophyll

chromodorid--a member of the family chromodorididae

circumtropical--having a global distribution in tropical waters

clavus--the club-shaped tip of a rhinophore

cnidosac--a sack in the tip of  a ceras that contains nematocysts extracted by aeolids from their food

columella--the inner margin of the aperture in a gastropod shell

columellar--relating to the columella

commensal--an animal that lives in close association with another species without harming its host

cosmopolitan--having a global distribution in tropical and temperate waters

cryptic--a species that is difficult to see against it's usual background

cryptobranch--dorids that can fully withdraw their gills (or that have evolved from such species)

cusp--a lump or projection on the surface of a tooth

cyanobacteria--photosynthetic bacteria, also known as blue-green algae

dendrodorid--a member of the family denrodorididae

dendronotid--a member of the suborder dendronotacea

denticle--a tooth-like bump or projection

denticulate--having denticles

dioecious--having male and female organs in separate individuals

digestive gland--the primary organ responsible for digestion in opisthobranchs, often highly elaborate

digitiform--resembling fingers

direct development--lacking a larval stage

distal--the portion of a structure furthest from the body

diverticulum--a blind pouch or sack, usually part of the digestive gland

dorid--a member of the suborder doridacea

doridiform--resembling a dorid in body plan

dorsal--referring to the upper surface of an animal

dorsal slit--the opening between the parapodia in anaspideans

dorsum--the upper surface of an animal

elysiid--a member of the family elysiidae

endemic--a species found only in the region under discussion

epibiont--an organism that lives on the surface of another organism

epiphyte--a plant that lives on the surface of another plant

extra-branchial appendage--a projection from the body located near the branchia in some dorids

extra-capsular yolk--yolk deposited outside the egg capsule

extra-rhinophoral appendage--a projection from the body located near the rhinophores in some dorids

eye spots--the simple eyes found in opisthobranchs

facultative--a trait or posture that is displayed only under some circumstances

--the organ used by mollusks for crawling

foot corners--the anterior corners of the foot

frontal veil--the expanded anterior portion of the head in many dendronotids

genital aperture--the reproductive opening in the body wall

genital pore--the reproductive opening in the body wall

gill--a structure used for respiration

gizzard plate--a crushing plate in the oral cavity of cephalaspideans

head shield--the flattened, fleshy plate covering the head  region in cephalaspideans

head shield slug--a member of the order cephalaspidea

hermaphrodite--being both male and female

holoplanktonic--organisms that spend there entire life cycle in the plankton

Indo-Pacific--a faunal province encompassing the tropical waters of the Indian and Pacific oceans but not the west coast of the Americas.

inflated--swollen or expanded

in situ--in its original place or location

intergrades--intermediate forms between two morphologies

interspecific variation--variation between species

intraspecific variation--variation between members of the same species

involute--rolled inward

jaw--a chitinous structure used to hold prey

juliid--a member of the family juliidae

kleptoplastids--the functional chloroplasts that Sacoglossans retain from their algal food

labial--pertaining to the mouth or lips

labial tentacles--projections originating near the mouth

lamella (plural: lamellae)--a leaf-like fold

lamellate rhinophores--rhinophores having leaf-like folds

lecithotrophic--larvae that spend only a short time in the plankton before settling and do not feed while planktonic

maculations--spots or blotches

mantle--the portion of the integument of mollusks that secretes the shell

mantle cavity--a chamber housing the gills in prosobranchs and some opisthobranchs

mantle gland--glands in anaspideans that produce a purple or milky fluid, presumably defensive

median--pertaining to the center

mimicry--when one species resembles another, presumably gaining some selective advantage

monoecious--having male and female organs in the same individual

monophyletic--a group that includes all the descendants of the most recent common ancestor of its members

monotypic--a taxon that contains only one species

mullerian mimicry--when two unpalatable species resemble each other

nematocyst--a stinging cell produced by cnidarians (jellyfish, etc)

nephridiopore--urinary pore

nomenclatural--having to do with names

notal--relating to the notum

notaspidean--a member of the order notaspidea

notum--the upper surface of an animal

nudibranch--a member of the order nudibranchia

ocellate--having ocelli

ocellus (plural: ocelli)--ring-like spots resembling eyes

octocoral--a member of the cnidarian subclass octocorallia, one of the groups known as "soft corals"

opaline gland--a gland in aplysiids that produces a milky fluid

operculum--the plate that many gastropods use to seal the apertures of their shells

opisthobranch--a member of the subclass opisthobranchia

oral hood--the expanded "net" used by the genus Melibe to catch food

oral tentacle--a projection emerging near the mouth

oral veil--the expanded front of the head in many dendronotids

oscules--the larger, excurrent, pores in sponges

ostia--the smaller, incurrent, pores in sponges

ovigerous--containing or bearing eggs

palmate cerata--cerata resembling an open hand

papilla (plural: papillae)--a small, finger-like  projection or bump

papillate rhinophores--rhinophores having papillae

paraphyletic--a group that does not include all the descendants of the most recent common ancestor of its members

parapodium (plural: parapodia)--the lateral projections of the body wall that enclose the mantle cavity

parapodial--relating to the parapodia

patelliform--having a cap-shaped shell

pelagic--living in the open ocean, refers to actively swimming species of surface waters

pericardium--the simple heart in opisthobranchs (= cardiac sack)

periostracum--the outer layer of a gastropod shell

phanerobranch--dorids that cannot fully retract their gills

phyllidiid--a member of the family phyllidiidae

pinnate--feather-like in form with small projections extending from both sides of a central axis

planktonic--drifting passively in the open ocean

planktotrophic--larvae that spend a prolonged period in the plankton before settling

plastids--pigment containing organelles in the cells of algae and other plants

pleurobranch--a member of the order pleurobranchomorpha (formerly included tylodinoidea)

polyphyletic--a group that does not include the most recent common ancestor of all its members

posterior--pertaining to the rear of the body

posterior shield--the posterior portion of the body in cephalaspideans

process--a projection, usually elongate

prosobranch--gastropod mollusks of the subclass prosobranchia

protoconch--the larval shell in gastropod mollusks

proximal--the portion of a structure closest to the body

pulmonate--gastropod mollusks of the subclass pulmonata

punctate--covered with small pits or depressions

pustule--a mound or low projection, often under muscular control

rachis--the central stalk or "rib" of a branchial plume

radula--the toothed structure used by most mollusks in feeding

radular teeth--the horny teeth that cover the radula

rhinophore--one of the tentacles on top of the heads of most opisthobranchs, presumably sensory in function

rhinophore shaft--the stalk or "trunk" of a rhinophore

rhinophore sheath--the collar or cup surrounding the base of a rhinophore

rolled rhinophores--flattened rhinophores that have inrolled margins forming a tube

rosette--a circular cluster of branches or projections

sacoglossan--a member of the order sacoglossa

sap sucking slug--a member of the order sacoglossa

scleractinian--a member of the cnidarian order scleractinia, most species referred to as "hard corals"

sea butterfly--a member of the order thecosomata

sea hare--a member of the order notaspidea

sea slug--a member of the subclass opisthobranchia, particularly those that lack shells

secondary metabolites--chemicals created by an animal from compounds in their food

sensory bristles--fine projections that presumably provide tactile information in aglajids

side-gilled slug--a member of the order pleurobranchomorpha (formerly included tylodinoidea)

simple rhinophores--rhinophores that lack any obvious ridges, lamellae or other "decorations"

siphon--a tube-like extension of the mantle used for circulating water

solution bench--a sandstone bench formed at about sea level by chemical and microbial action (= accretion platform)

spicule--a tiny, reinforcing structure formed by sponges and some opisthobranchs (among others)

spire--the apical portion of a gastropod shell

stria (plural: striae)--a fine line or ridge

subapical--immediately below the apex of a structure

submarginal--located bellow the edge or margin of a structure such as a parapodium

subterminal--immediately below the end of a structure

suture--the place where two structures join, particularly two whorls of a gastropod shell

symbiont--an animal that lives in close association with another animal

taxon (plural: taxa)--a group used in the classification of organisms such as genus, family, order, class, etc.

sympatric species--species that have overlapping ranges

tentacle--a long projection, usually sensory in function

tentaculiform foot corner--foot corners that are elongated to form sensory tentacles

tripinate--branching in three cycles from the central axis

tubercle--a small projection or lump, usually larger than a papilla

umbilicus--the axial opening around which a gastropod shell coils

veil--a membrane-like extension of the head

veliger--the larvae of gastropod mollusks

velum--a ciliated structure in gastropod larvae used for swimming

ventral--pertaining to the lower side

verrucose rhinophores--rhinophores having irregular wrinkles

villi--finger-like or thread-like projections from a surface

villous--covered with small, hair-like projections (villi)

visceral mass--the internal organs of an opisthobranch

whorl--one "turn" of a gastropod shell

zooxanthellae--the symbiotic algae that live within the bodies of cnidarians, mollusks, etc.
Species list