500 ZOOLOGY. 
is the copperhead (Ancistrodon contortriz 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 (Titanophis), 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 serpent-like forms, with paddle-like feet, which 
are regarded by Cope asthe 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 
amaximus 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 F. 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 (Varanide) ; 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 iong 
forked tongue. The very long tail was flat and deep, like 
that of a great eel, forming a powerful propeller. The 
* The sequence of orders of reptiles should be as on page 517. 
