CLASSIFICATION OF VENUS (SALTWATER CLAM)
KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle.)
CLASS :- PELECYPODA OR BIVALVIA (Bivalve shell.)
ORDER :- VENERIDA (Gill filaments united by inter-filament and inter-lamellar junctions.)
FAMILY :- VENERIDAE (Shell sculpture tends to be primarily concentric)
GENUS :- Venus (Saltwater clam)
It is found in India, Europe and U.S.A. (Gulf of St. Lawrence to Texas).
HABIT AND HABITAT
Venus is a burrowing form in muddy and sandy flat, near the lower portion of the inter-tidal zone of the Atlantic coast ciliary mode of feeding.
GENERAL CHARACTERSTICS OF VENUS (SALTWATER CLAM)
- Commonly called as hard-shelled clam and little-neck clam.
- Shell is composed of two symmetrical halves covered by equal shell valves which are dorsally joined by hinge ligament.
- Shell is ovate or heart-shaped, anterior end short, posterior end rounded.
- Umbo directed forwards, shell surface dirty white with prominent, sharp, concentric ridges.
- Small incurrent siphon and large excurrent siphon separated.
- Inner surface is smooth dull white with violet or lower granulated margin. Various structures seen are Umbo, fringed margin, pallial sinus, pallial line, ligament, anterior adductor scar, posterior adductor scar, anterior lateral tooth and cardinal tooth.
- Siphons short, unequal and more or less separated.
- After removing the left shell valve various internal structures seen are beak, anterior foot, retractor muscle, liver, labial palps, anterior adductor muscles, gonad, gill, posterior adductor muscle, kidney bulbous arteriosus, ventricle and pericardium.
- Although it lies buried a few inches, it keeps its siphonal end above the surface of the mud in order to maintain a current of sea-water through its body for feeding.
- Lunule is a heart-shaped configuration, which lies anterior and ventral to the beak.
- Spawning takes place in rainy season. Millions of eggs and sperms are produced. Young clam lies dormal1t for 2 years.
Extensively used as food. It is also, used for manufacture of wampum, the violet portion forming the most valuable pieces.
The animal has fringed margin in the shell and all above character hence it is Venus.