Title: A manual of zoology
Identifier: cu31924031530540 (find matches)
Year: 1912 (1910s)
Authors: Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929, ed. and tr
Subjects: Zoology
Publisher: New York, H. Holt
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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IV. VERTEBRATA: REPTILIA, RHYNCHOCEPHALIA. 527 condition of the quadrate, the lack of an os transversum and of any but basi- sphenoid of the sphenoidal bones (Dennochelys has a parasphenoid), and the growth forwards and backwards by which the girdles are brought inside the ribs. The teeth are entirely lost, and, as in birds, the jaws are enclosed in sharp horny beaks, in many cases efficient weapons against larger vertebrates. The cloaca! opening is oval, its major axis corresponcUng to that of the body, and in its anterior end is an unpaired erectile penis used in copulation. Turtles appeared in the Permian. Characters of armor and legs serve to contrast sharply the land and sea turtles; the first with well-developed legs, iive-toed in front, four-toed behind, the toes with claws; the carapace arched, into which legs, head, and tail may be retracted. In the sea turtles the feet are flipper-like (fig. 576), claws mostly absent, and the carapace weakly united to or free from the plastron, flat and incapable of covering head or appendages. The fresh-water species are inter- mediate in position. Sub Order I. ATHECA. Carapace of numerous mosaic scales not con- nected with ribs and vertebrfe; skin leathery. Dermnchelys* leather-back tortoise, reaches a weight of 1500 pounds. Sub Order II. TRIONYCHIA. Fresh-water forms with poorly ossified carapace, but ribs and vertebras connected with it. Leather turtles (Amyda*) and soft-shelled turtles LAspidonectes*).
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Fig. 576.—Eretmochelys inibricata, tortoise-shell turtle (from Hajek). Sub Order III. CRYPTODIRA. Carapace well developed and united with ribs and vertebrae, but the pelvic arch free. Species numerous, including ter- restrial, fresh-water, and marine forms. Chelydrid^, fresh water, tail long. Chelydra serpentina* snapping turtle; Machrochelys lacerlina* alligator turtle. Chelonid.5;, marine, paddle-like feet. Thalassochelys* loggerhead; Chelone mydas* green turtle; Eretmochelys imbricala, whose horny shields furnish 'tortoise shell.' Testudinid.5;, terrestrial, including Xerobates,'*- the 'gopher turtle' of the South, the giant Testudo of the Galapagos Islands, and the fossil Colossochclys atlas of India, 18-20 feet long, 8 feet high. Other families contain our mud turtle (Kinosternon*), box turtles (Cistiido), and terrapins (Mala- demmys*). Sub Order IV. PLEURODIRA. Pelvis united to carapace and plastron; southern hemisphere. Order V. Rhynchocephalia. These resemble the lizards not only in body form (four five-toed feet) and in scaly skin, but in lack of hard palate, presence of epipterygoid, transverse cloacal opening, and heart, lungs, and brain. On the other hand, they recall crocodiles in having two postorbital arches and immovable quadrate. The large abdominal sternum and abdominal ribs are noticeable as well as the uncinace processes of the true ribs. The notochord is but incompletely replaced, the vertebrcB amphicoelous. The group appears in the Permian and is one of the

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