Molluscs Flashcards
Head and radula disappeared
Bivalves
Flat heart-shaped area and found along the umbones and escutcheon
Lunule
It is also called the shape of the shell. Shapes include: trigonal, quadrate, rhomboidal, trapezoidal. Can also be orbicular, oval, oblong ovate, pyriform, elongate. Anterior and posterior ends may be rounded, obtuse pointed, truncate, or rostrate.
Outline
can be of various colors and may be hairy or pills in some forms. Can be smooth or with ornaments or with markings referred as sculpture.
Periostracum
Ear shaped anterior and posterior are called
Ears or auricles
Longer projections along hinge lines are called
Wings and shell alate
Rotund or swollen shells are called
Inflated
According to the location of the beak, the shell is EQUILATERAL when the beak is (1) ______ and their anterior and posterior end of each valves are _____. And INEQUILATERAL when (2) _____ and their posterior and anterior of each valves are ______.
- Central or medial, equal sizes
- Not central, unequal
Bilaterally symmetrical, unsegmented animals with usually definite head and muscular foot for locomotion
Molluscs
It houses the gills or lungs, anus and excretory pores
Mantle cavity
A rasping organ
Radula
Most molluscs are ____ with some forms of ___
Dioecious, hermaphroditic
Fertilization is external with transfer of
Spermatophores
The life cycle of molluscs includes a ____ which is the characteristic of ____
Ciliated trocophore larva, marine annelids (which naay strong embryological evidence that molluscs are related to annelids)
What ranges of size does molluscs have
Microscopic to largest invertebrates
A two small group which are worm-like with no shells
Caudofoveta and Solenogastres
It possess a tubular shell open at both ends
Scaphopoda
Most successful largest class of molluscs
Gastropoda
Common marine forms with shells in longitudinal series of eight plates
Polyplacophora
Are marine and fresh-water and have shell divided into left and right valves
Class Bivalvia (Pelecypoda)
Second most abundant group next to the arthropods
Molluscs
Laterally compressed body, enclosed in two-lobed mantle often extended to form incurrent and excurrent siphons.
Bivalvia
