Body Parts (Exam 1) Flashcards
Medusa:
Pelagic, sac-like body form or growth stage (Cnidarians)
Polyp:
Benthic, barrel-like body form or growth stage (Cnidarians)
Radial symmetry:
Multiple vertical symmetry planes radiating outward from the center (Cnidarians)
Basal Disc:
Flattened bottom of the polyp, where it attaches to the substrate.
Oral Disc:
Flattened top portion of the polyp, on which the mouth occurs. (Cnidarians)
Mouth:
The single opening to the central cavity (enteron) (Cnidarians)
Pharynx:
Throat-like tube leading from mouth into the central cavity (enteron). (Cnidarians)
Tentacles:
Arm-like, cnidoblast-bearing structures surrounding the mouth. (Cnidarians)
Enteron:
Central body cavity, which contains mesentery and digestive tissues. (cndarians)
Mesenteries:
Radiating vertical sheets of tissue (Cnidarians)
Cnidoblasts:
“stinging cells”, which contain the poisonous nematocysts (Cnidarians)
Nematocysts:
Toxin-bearing sacs within the cnidoblasts (Cnidarians)
Corallum:
Skeleton of the entire coral colony
Corallite:
Skeleton of a single coral polyp.
Theca:
Outer wall of corallite
Calice:
Bowl-shaped top surface of corallite.
Fossula:
Deep, slot-like indentation in calice.
Columella:
Pillar (axis) in center of corallite.
Septa:
Radiating, vertical, blade-like partitions inside corallite.
Tabulae:
Stacked, horizontal, platform-like partitions inside corallite.
Dissepiments:
Multiple domed plates connecting the septa inside corallite.
Ostium:
Small pore in the sponge wall, through which water enters the body.
Canal:
Tubular channel starting at an ostium and extending through the sponge wall.
Spongocoel:
Large cavity in the interior of the sponge body
Osculum:
Large opening, through which water is expelled from the spongocoel.
Spongin:
The soft, flexible, organic material that makes many sponges “spongy”
Spicules:
Tiny, hard, needle-like structures of either silica or calcite (not all sponges have these)
Zoarium:
Skeleton of the entire bryozoan colony; may assume various growth forms, such as encrusting, massive, branching (bush-like or stick-like), etc.
Zoecium:
Body wall or skeleton iof individual bryozoan animal
Aperture:
Main opening in zoecium through which the animal brings in water & food
Operculum:
Hinged lid covering the aperture of some bryozoans (Cheilostomes)
Zooid:
Individual bryozoan animal; typically <1mm in diameter
Ancestrula:
Initial (sexually produced) zooid of the colony. (Bryozoan)
Kenozooids:
Individuals specialized for asexual budding of other zooids in the colony. (Bryozoan)
Gonozooids:
Individuals specialized for producing gametes (sex cells)
Autozooids:
Normal feeding individuals within the colony.
Rhabdosome:
Entire graptolite colony
Zooid:
Individual graptolite animal
Theca:
Chitinous shell of an individual zooid
Sicula:
The single, conical theca of the first zooid in the colony; attached at top end to the nema
Nema:
Hollow thread-like structure extending from the top of the sicula
Stipe:
Single branch of a colony, containing a string of thecae.
Dissepiments:
Connections between the stipes of some types of rhabdosomes
Lophophore:
Distinctive feeding structure inside the brachiopod shell, consisting of two arm-like “brachia” that bear cilia, which beat back and forth in the water to create microcurrents and strain suspended food particles from the water; attached to inside of brachial valve.
Brachia:
Two arm-like branches of the lophophore; attached to brachial valve.
Pedicle:
Tough, fleshy stalk attached to pedicle valve and extending from the beak of the shell. (Brachiopod)
Mantle:
Thin sheet of tissue that lines the inside of the brachiopod shell
Periostracum:
Brown, scaley, organic “skin” coating the outside of some brachiopod shells.
Adductor muscles:
Muscles that close the two valves of the shell.
Diductor muscles:
Muscles that open the two valves of the shell (only found in Articulates).
Pedicle adjustor muscles:
Muscles that move the main body mass around at the end of the pedicle (only found in Articulates).
Oblique muscles:
Muscles that rotate and/or slide the two valves with respect to one another (only found in Inarticulates).
Valves:
The two main parts of the brachiopod shell
Brachial valve:
“Dorsal” valve, to which the lophopore is attached
Pedicle valve;
“Ventral” valve, to which the pedicle is attached.
Commissure:
Broad “anterior” margin of the shell opposite the pedicle and hinge.
Beak:
Pointed “posterior” end of the shell, from which the pedicle protrudes.
Hinge:
Structure at the beak that holds the two valves together and allows them to open and close in an articulated fashion (only found in Articulates).
Tooth & socket structure:
Small projections & corresponding pits on inside of the beak.
Interarea:
Outside pt of the shell located between the two pointed parts of the beak.
Pedicle Opening:
Hole or notch in the beak to allow the pedicle to protrude from the shell.
Foramen:
Round hole on the pedicle valve.
Delthyrium:
“V”-shaped notch on pedicle valve.
Notothyrium:
“V”-shaped notch on brachial valve.
Brachidium:
Calcareous lophophore support on insde of bracial valve (only in Articulates)
Crura:
Simple, forked brachidium in Rhynchonellids
Spiralium:
Ornate, coiled brachidium in Spiriferids
Loop:
Curved, lasso-like brachidium in Terebratulids
Fold:
Broad central ridge (usually on brachial valve) extending from beak to commissure.
Sulcus:
Deep central groove (usually on pedicle valve) corresponding to the fold.
Laminae
Individual, thin, calcite layers that make up the stromatoporoid skeleton.
Latilaminae:
Discrete units of multiple calcite laminae.
Pillars:
Long calcite rods within the latilaminae; oriented perpendicular to the laminae.
Mamelons:
Rounded bumps on the surface of a stromatoporoid skeleton.
Astrohizae:
Star-like arrangment of radiating, branching grooves on the mamelons.
Outer Wall:
Outermost of the two concentric walls of an archaeocyathid.
Inner Wall:
Innermost of the two concentric walls of an archaeocyathid.
Septa (Parietal Walls):
Rigid, radiating partitions that separate the outer and inner walls.
Intervallum:
Open space between the outer and inner walls.
Central cavity:
Open space inside the inner wall
Tip:
Pointed bottom end of the archaeocyathid skeleton
Holdfast:
Calcareous projections of the skeleton near its tip, which serves to anchor the archaeocyathid skeleton in place in the sediment.
