. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. MOLLUSCA. 257 line let fall fi-oiii the hinge divides the shell into two equal parts. The ventral valve has, in the great major- ity, a prominent beak, perfoi-ated by a foramen^ or hole, through which a fleshy foot protrudes to attach the ani- mal to submarine rocks. The valves are opened and shut by means of muscles, and in some cases they are hinged, having teeth and sockets near the beak. The mouth faces the middle of the y(ff»i'll« Fig. 214.—Dorsal Valve of a Brachiopod (Terebratula), showing, in
. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. MOLLUSCA. 257 line let fall fi-oiii the hinge divides the shell into two equal parts. The ventral valve has, in the great major- ity, a prominent beak, perfoi-ated by a foramen^ or hole, through which a fleshy foot protrudes to attach the ani- mal to submarine rocks. The valves are opened and shut by means of muscles, and in some cases they are hinged, having teeth and sockets near the beak. The mouth faces the middle of the y(ff»i'll« Fig. 214.—Dorsal Valve of a Brachiopod (Terebratula), showing, in desceudiug order, cardinal process, dental sockets, hinge-plate, septum, and loop support- ing the ciliated arms. Fig. 213.—a {Teiebratulina septenttiomilib). Atlantic coast. margin opposite tlie beak; and on either side of it is a long fringed " arm," gen- erally coiled up, and sup- ported by a bony frame - work. The animal, having no gills, respires either by the arms or the mantle. Bi-achi- opods were once very abundant, over 2000 extinct species having been described; but less than a hundred species are now ;' They are all marine, and fixed; but of all MoUusks, they enjoy the greatest range of climate and depth. Class IV.—Lamellibranchiata. Lamellibranchs are all ordinary bivalves, as the Oyster and Clam. The shells differ from those of Brachiopods in being placed on the right and left sides of the body, so that the hinge is on the back of the animal, and in being anequilateral and ;" The umbo answers to the 17. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Orton, James, 1830-1877. New York, Harper and brothers
Size: 1499px × 1666px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
