THEROMOliPHS. 457 



used as an article of food by tlie natives, and suffering from the introduction of hogs, 

 they have become uncommon, and will soon be numbered with the animals which once 

 existed but are now extinct. 



Of the fossil members of this order, the Proterosaurus is of particular interest, as 

 it was the first known fossil reptile, being described as early as 1710 from fragments 

 obtained in the permian beds of Thuringia. A study of the bones of the head, neck, 

 and limbs shows it to have been an aquatic animal of considerable size, cai)able of seiz- 

 ing and retaining the active fishes which sported in the waters tiiat deposited the old 

 Thuringian coiiper-slates. Jihi/nchosaurus, from the trias of England, is of interest in 

 that the jaws, like those of turtles, arc unprovided with teeth, and the i)remaxillaries 

 present a curved beak, strongly resembling that of birds. The vertebral centra are, 

 however, like those of Ilatteria, biconcave. JJi/jxrodapedon, also triassic, is an allied 

 form. 



Order VI. — ICHTHYOPTERYGIA. 



The members of this order are all extinct, and are only known from their fossil 

 remains, which have been found in the tertiary deposits of the Old World. Though 

 true reptiles in structure, the Ichthyosauri resembled in general outline, and jn-obably 

 also in habits, the cetaceous mannnals of to-day. The broad head, short neck, thick 

 body and short vertebra3 resemble these portions of the whales, a general resemblance 

 carried still further by the flipper-like limbs and elongate, probal)ly fin-bearing, tail 

 which performed the ofHce of a proi}elIer. Some of these sauriuns were colossal in 

 size, reaching a length of forty feet, though many were smaller and resembled the dol- 

 phins, being about six feet or even less in length. That the animals were reptiles is at 

 once seen, however, on an examination of the brain cavity, wliich is of most diminu- 

 tive size when compared with that of sea-mammals, and is not protected by a solid 

 cranium, the bones of the head being more or less imperfectly united together. The 

 vertebral centra, moreover, were biconcave, and the orbits, which were enormous, some- 

 times fifteen inches in diameter, were protected by a circular series of triangular plates 

 which may have assisted in adjusting the focus of the eyes, or may have been in their 

 nature merely protective. A study of the jaws, as well as of the half-digested contents 

 of the alimentary tract, proves the Ichthi/osaiu'tts to have been a predatory animal, in- 

 habiting the open sea as well as the shores, and feeding on fish and other marine 

 animals. Though awkward in its movements, it not infrequently quitted the water 

 and crawled out on some exjtosed sand-bar to rest or to bask in the sun. J. communis 

 is the most common form. 



The fiauranodon, found in the Jurassic deposits of the west, rescinliled the Ichthyo- 

 saurus very closely, though it differed in being destitute of teeth. It is given by some 

 an ordinal, while others consider it of only family, value. 



Order VII. — THEROMORPHA. 



This order includes several extinct reptiles, fragments of which are found cliiefly in 

 the Permian and triassic fresh-water deposits of South Africa. The teeth are either 

 wanting or are represented by a j)air of maxillary teeth. The vertebnc are biconcave, 

 and the ambulatory limVjs are supported by a solid j)elvis and firm shoulder-girdle. It 

 was from this order that the mammals are by some supjjosed to have branched off, 



