Lab 4 Mollusca 1

Front 1

Adaptive radiation

Back 1

Evolutionary diversification that produces numerous ecologically disparate lineagesfrom a single ancestral one, especially when this diversification occurs within a short interval ofgeological time.

Front 2

Adductor muscle

Back 2

A muscle that draws a part toward a median axis, or a muscle that draws the two valves of a mollusc shell together.

Front 3

Byssal threads

Back 3

A strong elastic fiber used by some mussels to attach themselves to a solid substrate

Front 4

Captacula

Back 4

Tentacles extending from head of scaphopod molluscs, used in feeding.

Front 5

Cerrata

Back 5

Fingerlike projections along the dorsal sides of some nudibranches.

Front 6

Chromatophores

Back 6

Pigment cell, usually in the dermis, in which usually the pigment can be dispersed orconcentrated.

Front 7

Collar

Back 7

(1). Muscular structure extending from the nuchal cartilage to the funnel in a cephalopod. Thecollar forms a one-way valve that lets water enter the mantle cavity but closes as the mantlecontracts thereby forcing exhalent water out through the funnel. (2). A region on acorn worms(Hemichordata) where the mouth is located.

Front 8

Columella

Back 8

Central pillar in gastropod shells.

Front 9

Convergent Evolution

Back 9

Groups of unrelated organisms becoming similar in appearance because ofevolutionary change in response to similar environments.

Front 10

Countercurrent exchange

Back 10

The passive exchange of something between fluids moving in oppositedirections past each other

Front 11

Crop

Back 11

A pouchlike enlargement in the digestive tract of annelids and insects

Front 12

Ctenidium

Back 12

Comb-like respiratory structure serving as the gill, and for trapping food or sperm in certainmollusks

Front 13

Dextral

Back 13

Pertaining to the right; in gastropods, shell is dextral if opening is to right of columella whenheld with spire up and facing observer

Front 14

Excurrent siphon

Back 14

Siphon through which water exits in mussels

Front 15

Foot

Back 15

The muscular locomotory structure of molluscs.

Front 16

Funnel (siphon)

Back 16

The siphon of cephalopods.

Front 17

Gastric Shield

Back 17

A chitinized plate in the stomach of a bivalve (phylum Mollusca) on which the crystallinestyle is rotated.

Front 18

Hectocotylous arm

Back 18

Specialized, and sometimes autonomous, arm that serves as a male copulatoryorgan in cephalopods

Front 19

Hemocoel

Back 19

Main body cavity of arthropods and molluscs, which serves as a hydrostatic skeleton, but isnot a true coelom (see also pericardial cavity).

Front 20

Hemolymph

Back 20

Fluid in the coelom or hemocoel of some invertebrates that represents the blood andlymph of vertebrates.

Front 21

Incurrent siphon

Back 21

Siphon through which water enters in mussels

Front 22

Mantle

Back 22

The outer layer of tissue that secretes the shell of molluscs.

Front 23

Mantle Cavity

Back 23

The space between the mantle and the visceral mass of molluscs.

Front 24

Metanephridium

Back 24

An excretory organ found in many invertebrates; it consists of a tubule that has oneend opening at the body wall and the opposite end in the form of a funnel-like structure thatopens to the body cavity

Front 25

Nacreous layer

Back 25

Innermost lustrous layer of mollusc shell, secreted by mantle epithelium.

Front 26

Nematocysts

Back 26

An organelle characteristic of the Cnidaria that is used in defense, food gathering, andattachment.The stinging structure of cnidarians.

Front 27

Odontophore

Back 27

Tooth-bearing organ in molluscs, including the radula, radular sac, muscles, andcartilages.

Front 28

Open circulatory system

Back 28

A circulatory system in which blood is not confined to vessels in a part of itscircuit within an animal; blood bathes tissues in blood sinuses.

Front 29

Operculum

Back 29

A cover. The cover of the nematocyst. The cover of the aperture of a snail shell(Prosobranchia, Gastropoda, Mollusca).

Front 30

Osphradium

Back 30

A sense organ in aquatic snails and bivalves that tests incoming water

Front 31

Pallial line

Back 31

Line along the inside margin of molluscan bivalve shell where the mantle tissue is attachedto the shell.

Front 32

Palp

Back 32

An elongated, often segmented appendage usually found near the mouth in invertebrateorganisms such as mollusks, crustaceans, and insects, the functions of which include sensation,locomotion, and feeding. Also called palpus.

Front 33

Pedal retractor muscle

Back 33

Muscle that serves to retract the foot of a mollusc into the shell

Front 34

Pen

Back 34

In squids, a thin, chitinous structure extending the length of the mantle tissue

Front 35

Pericardial cavity

Back 35

Cavity around heart; the coelom of molluscs.

Front 36

Periostracum layer

Back 36

Outer horny layer of a mollusc shell.

Front 37

Pnemostome

Back 37

The opening of the mantle cavity (lung) of pulmonate gastropods to the outside.

Front 38

Prismatic layer

Back 38

Middle layer of the mollusc shell, containing densely packed cells of calcareous materialsecreted by the edge of the mantle.

Front 39

Protandric hermaphrodites

Back 39

A pattern of sexuality in which a single individual functions as male andthen female in sequence

Front 40

Radula

Back 40

The rasping, tonguelike structure of most molluscs that is used for scraping food; composed ofminute chitinous teeth that move over a cartilaginous odontophore.

Front 41

Rhinophores

Back 41

Chemoreceptive tentacles in some molluscs (opisthobranch gastropods).

Front 42

sequential hermaphrodites

Back 42

The type of hermaphroditism that occurs when an animal is one sex duringone phase of its life cycle and an opposite sex during another phase.

Front 43

Shell

Back 43

The calcium carbonate outer layer of cnidarians, molluscs, and other animals. Produced bymucous glands

Front 44

Simultaneous hermaphrodites

Back 44

An organism with both male and female sexual organs at the same timeas an adult

Front 45

Sinistral

Back 45

Pertaining to the left; in gastropods, shell is sinistral if opening is to left of columella when heldwith spire up and facing observer

Front 46

Spicules

Back 46

One of the minute siliceous skeletal bodies found in sponges. Calcareous pines in the shell-lessClass Aplacophora (Mollusca)

Front 47

Style

Back 47

Slender, elongated mouth part, e.g., of an insect, used for stinging or piercing prey or sucking sap.A spear-like mouthpart used to penetrate plant tissue in plant pathogenic nematodes

Front 48

Suckers

Back 48

An organ specialized for sucking nourishment or for adhering to objects by suction.

Front 49

Torsion

Back 49

A developmental twisting of the visceral mass of a gastropod mollusc that results in an anterioropening of the mantle cavity and a twisting of nerve cords and the digestive tract.

Front 50

Trochophore larva

Back 50

A larval stage characteristic of many molluscs, annelids, and some otherprotostomate animals.

Front 51

Umbo

Back 51

One of the prominences on either side of the hinge region in a bivalve molluscshell. Also, the "beak" of a brachiopod shell.

Front 52

Veliger larva

Back 52

Larval form of certain molluscs; develops from the trochophore and has the beginning of afoot, mantle, shell, and so on.

Front 53

Visceral mass

Back 53

The region of a mollusc's body that contains visceral organs