. East coast marine shells : descriptions of shore mollusks together with many living below tide mark, from Maine to Texas inclusive, especially Florida, with more than one thousand drawings and photographs . long periods out of water, and rank next to the Gastropoda in variety of forms. The bivalves individually, however, are much more plentiful. Normally the Pelecypod shell con- sists of two valves, distinct and separate, usually covering the right and left sides of the animal. Margins of Shell. The hinge line, along which the valves are united by the ligament and interlocking teeth, is plac
. East coast marine shells : descriptions of shore mollusks together with many living below tide mark, from Maine to Texas inclusive, especially Florida, with more than one thousand drawings and photographs . long periods out of water, and rank next to the Gastropoda in variety of forms. The bivalves individually, however, are much more plentiful. Normally the Pelecypod shell con- sists of two valves, distinct and separate, usually covering the right and left sides of the animal. Margins of Shell. The hinge line, along which the valves are united by the ligament and interlocking teeth, is placed upon the dorsal region of the animal and forms the upper or DORSAL MARGIN of the shell. Fig. 19a. The opposite side is the VENTRAL or LOWER MARGIN, Fig. 19b, and is often thin and sharp. The POSTERIOR or SIPHONAL END, Fig. 19d, refers to the end upon which the ligament is situated, at the opposite extremity is the ANTERIOR MARGIN or ANTERIOR END; Fig. 19e. Right and Left Valves. The valves are right or left depending upon the side of the animal. To Identify these the shell should be placed in position as when crawling, the ligament upward and toward the observer, the anterior or opposite end pointing forwards. The right or left valves then agree with the student's right or left hands. On PI. 54, Fig. 8, representing a large clam, the ligament is shown distinct- ly. In this illustration the right- hand point is the anterior end, the lower valve the right valve. Fig. 19 Parts of bivalve shell, 19a Dorsal margin, 19b Ventral margin, 19c Ligament, 19d Pos- terior end, 19e Anterior end, 19f umbo, 19g Position of lunule, 19h Cardinal teeth, 19J Anterior latertil tooth, 19k Posterior later- al tooth, 19/ anterior adductor, 19m Posteri- or adductor, 19n Pallial line, 19o Pallial sinus
Size: 2528px × 1977px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
