. A manual of zoology. Zoology. IV. VERTEBRATA: REPTILIA. 521 Class I. Reptilia. On account of similarity of form, the reptiles and Amphibia were long untied. They form parallel groups: urodeles and lizards, frogs and turtles, cceciUans and snakes. Hence the points of distinction must be emphasized. The most important are two: the reptiles belong to the Amniota and, as such, have the embryonal features of the group; second, although often aquatic, they are, in the entire absence of branchial respira- tion, in character of skin and skeleton, in their entire structure, like the true land animals
. A manual of zoology. Zoology. IV. VERTEBRATA: REPTILIA. 521 Class I. Reptilia. On account of similarity of form, the reptiles and Amphibia were long untied. They form parallel groups: urodeles and lizards, frogs and turtles, cceciUans and snakes. Hence the points of distinction must be emphasized. The most important are two: the reptiles belong to the Amniota and, as such, have the embryonal features of the group; second, although often aquatic, they are, in the entire absence of branchial respira- tion, in character of skin and skeleton, in their entire structure, like the true land animals. The skin, the better to withstand desic- cation by the air, is strongly cornified, so that in the epidermis a many-layered stratum corneum and a many-layered stratum Malpighii can be distinguished. At the tips of the toes the stratum corneum develops strong claws on the dorsal side, the claw plate being better developed than the ventral claw sole. Further protection is afforded by the thick corium in which not infrequently bony plates occur. Dermal glands are very rare, the femoral pores of hzards (fig. 577, b), which appear like the ducts of glands, being produced by the ends of cornified epithelial cones. Here must be mentioned the dorsal, anal and musk glands of the crocochles. The axial skeleton, both skull and vertebral column, is nearly always ossified; only {Splienodon and the am- phiccele Ascalabotae) are considerable parts of the notochord retained. The vertebraj are usually procoelous. In the skull of i:t7iFm£. Oi C'occ Oa, Fig. 572.—Ventral view of skull C'f Tropidonotus (from Wiedersheim). Bp, basioccipital; Bs, basisphenoid (in front also parasphenoid); Ch, choana; Cocc, occipital condyles; Elh, ethmoid cartilage; F, frontal; i^o, fenestra ovalis; M, maxillar}'; ol, cipital; P, parietal; P/, prefrontal; PI, palatine; Pmx, premaxillary; Pt, pterygoid; Qu, quadrate; 5(?M, squamosal; Ts, transversum; Vo, vomer; 77, optic foramen. reptiles (a
Size: 1235px × 2023px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
