. A manual of elementary zoology . Zoology. COLD-BLOODED VERTEBRATA 3»S Botalli and ductus arteriosus that are persistent in the Common Newt, is also complete; in other cases both ductus remain open, and so on. In the kidneys of the newt there is a distinction between the so-called meso- and metanephros, which recalls the condition of these organs in the dogfish. Reptiles1 resemble Am- Reptma. Phibians in being cold- blooded, lung - breathing, pentadactyle vertebrates, but they have an exo- skeleton of horny scales, with sometimes also bony plates, twelve cranial nerves,2 stout, usually chalky
. A manual of elementary zoology . Zoology. COLD-BLOODED VERTEBRATA 3»S Botalli and ductus arteriosus that are persistent in the Common Newt, is also complete; in other cases both ductus remain open, and so on. In the kidneys of the newt there is a distinction between the so-called meso- and metanephros, which recalls the condition of these organs in the dogfish. Reptiles1 resemble Am- Reptma. Phibians in being cold- blooded, lung - breathing, pentadactyle vertebrates, but they have an exo- skeleton of horny scales, with sometimes also bony plates, twelve cranial nerves,2 stout, usually chalky shells to their eggs, no larvae, and in their em- bryos amnion and allan- tois, which we have already mentioned (see p. 506). They comprise Turtles, Crocodiles, Snakes, Lizards, and the Tuatara, a little lizard-like animal found in New Zealand. Thus when popular speech calls frogs, toads, and newts " reptiles " it is not strictly correct, though Amphibians may justly be said to be more. Fig. 278.—The skull of Capito- saurus nasutus, one of the Stegocephali. — From Rey- nolds, after von Zittel. i, Premaxilla; 2, nasal; 3, maxilla; 4, anterior nares ; 5, frontal; 6, pre- frontal {or lachrymal); 7, lachrymal {or adlachrymal) ; 8, jugal; 9, orbit; 10, parietal; n, postfrontal; 12, post- orbital ; 13, interparietal foramen ; T4, squamosal {or supratemporal); r5, supratemporal {or prosquamosal); 16, quadratojugal; 17, quadrate; 18, epiotic {or tabulare); 19, dermal supra- occipital {or postparietal); 20, exoc- cipital; 2r, foramen magnum. The sheet of membrane bones which forms the roof of this skull is a special development of the armour of bony scales which is found on other parts of the body of Stegocephali. It is not only the roof of the cranium, but stretches over the space nparlv ntin rn rpnrilpc than Detween tne cranium and the upper jaw nearly aKin tO repilieS man (palato-pterygo-quadrate bar). In most to any animals. other class of other bony skulls, gaps (th
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