500 ZOOLOGY. 



is the copperhead {Ancistrodon contortrix Linn.) and the 

 black mocassin {Ancistrodon piscivorus Linn. ). In the water 

 snakes the tails are laterally compressed, while the poison- 

 fangs are small. These snakes are not much over a metre in 

 length, and live far from land in the East Indian seas. 



The poisonous snakes stand lowest in the series ; they are 

 succeeded by the striped snake, milk adder, and by the boas, 

 which attain a length of five metres ; while the anaconda 

 grows eight metres long. 



In time snakes reach back to the Eocene Tertiary period, 

 when a great sea-snake (Titanophi.s), represented by several 

 species, one six metres in length, haunted the coast of New 

 Jersey, while in the western lake-deposits of the same age, 

 forms allied to the existing boa-constrictor were not un- 

 common. The snakes, then, appear to be a modern type 

 compared with the lizards, turtles, and crocodiles. 



Order 2. Pythonomorpha.. — This group includes a num- 

 ber of colossal serpeut-like forms, with paddle-like feet, which 

 are regarded by Cope as the types of a distinct order, char- 

 acterized by a complex suspensorium, by the absence of a 

 sternum and sacrum, by the rootless teeth, recurved parie- 

 tal bones, etc. 



They were fifty and sixty feet in length, and Mosasaurus 

 maximus Cope, from New Jersey was still more colossal. 

 They combined characters of the snakes, lizards, and plesio- 

 saurs, and correspond in a degree to the descriptions of the 

 mythical sea-serpent. 



The resemblance to the Ophidians is still farther strength- 

 ened by the late discovery by Professor P. H. Snow, that one 

 of the forms (Liodon) was covered, above by small imbricated 

 scales, like those of the snakes, rather than large ones, like 

 those of lizards. The more abundant type is the Mosa- 

 saurus of the Cretaceous seas, which was a huge sea-serpent 

 originally referred by Cuvier and Owen to the neighborhood 

 of the lace-lizards ( Varanidm) ; Cope describes it as a long 

 slender reptile, with a pair of powerful paddles in front, a 

 moderately long neck, and flat pointed head, with a long 

 forked tongue. The very long tail was flat and deep, like 

 that of a great eel, forming a powerful propeller. The 



