. Outlines of zoology. Zoology. EXTINCT REPTILES. 59i with the Chelonia. Nothosaurus had limbs adapted for progression on land; Plesiosaurus and Pliosaurus were carnivorous forms adapted to an aquatic life. Plesiosaurus had a. very long neck, and sometimes attained a length of 40 ft. In Pliosaurus the neck was much shorter, while the head was very large. In both, the limbs form powerful elongated paddles, with apparently no trace of nails. Ichthyosaiiria. — Large marine carnivorous Reptiles, represented from the Trias to the Chalk, with tapering body like that of a shark, large dorsal and caud
. Outlines of zoology. Zoology. EXTINCT REPTILES. 59i with the Chelonia. Nothosaurus had limbs adapted for progression on land; Plesiosaurus and Pliosaurus were carnivorous forms adapted to an aquatic life. Plesiosaurus had a. very long neck, and sometimes attained a length of 40 ft. In Pliosaurus the neck was much shorter, while the head was very large. In both, the limbs form powerful elongated paddles, with apparently no trace of nails. Ichthyosaiiria. — Large marine carnivorous Reptiles, represented from the Trias to the Chalk, with tapering body like that of a shark, large dorsal and caudal fins, and two pairs of paddle-like limbs. There is no exoskeleton. The length of the body is sometimes 30 to 40 ft. In the paddle the number of digits is often more than five, and the phalanges of each are often very numerous. The skull has a large parietal foramen, and shows other affinities with that of Sphenodon. Some species were apparently viviparous. Examples.—Ichthyosaurus, Ophthalmosaiints. Pythonomorpha.—These strange Cretaceous Reptiles should probably. Fig. 257.—Comparison of pelvic girdles of cassowary (to left) ; Iguanodon, an extinct Reptile (in centre) ; crocodile (to right). //., Ilium ; Is., ischium; P., pubis. be placed between the Lacertilia and the Rhynchocephalia. They are specially characterised by the enormous elongation of the body, which sometimes reached a length of 75 to 80 ft. The skull is like that of the Monitor among the lizards, but, according to Cope, it also presents affinities with snakes. The body is snake-like, but there are two well- developed pairs of limbs, forming swimming paddles. All were car- nivorous and marine ; the distribution was cosmopolitan. Examples.—Mosasaurus, Clidastes, Liodon, Dolichosaurus. Dinosauria.—Terrestrial Reptiles, ranging from the Trias to the Chalk, often very large, and, like Marsupials, specialised in various directions. They exhibit many points of resemblance to Crocodiles on the one side and
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
