MIOCENE PERIOD 167 



Tortoises, turtles, crocodiles, and alligators, however, 

 seem to have been less rich in species than of old, and prob- 

 ably in most parts of the world they were in a declining 

 condition. 



Lizards and snakes, on the other hand, were steadily LIZARDS 

 advancing. Of the former reptiles, in addition to creatures 

 closely resembling those of earlier times, various new kinds 

 abounded. Some of these are not identifiable with living 

 genera ; but spotted or " eyed " lizards, skunk lizards, and 

 so-called " glass snakes " seem now to have issued from the 

 more or less hotch-potch condition of old lizard-life 

 (Dracanasaurus, Locellata, Ophisaurus}. Snakes comprising SNAKES 

 hitherto innocuous forms only were now diversified by 

 cobras, rattle-snakes, and other purveyors of venom (Naia, 

 Neurodronicus, Bitis). 



Amphibian life had for a long time been on the decline, AMPHIBIANS 

 and from once possessing huge warriors had come down to 

 a humble representation consisting of frogs, toads, newts, 

 and salamanders. In this Period, however, some revivalists 

 of lost glory appeared in the form of big frogs and sala- 

 manders. The largest of the frogs were some eight inches 

 in length. These giants of their kind were probably ancestors 

 of the venomous horned frogs now living in Brazil (Latonia). 

 Some of the salamanders attained a length of over three feet 

 (Cryptobranchus). They were certainly big for salamanders, 

 but they fell far short of the " roofed-head " giants of Triassic 

 and still remoter times (Stegocephs). Indeed, the total 

 length of the largest of them did not equal the skull-length 

 of some of the old " roofed heads." Nor did they hold any 

 close relationship with those amphibious monsters. Like 

 the big frogs, they were not without an elixir of life ; and at 

 the present day salamanders are to be found in Japanese 

 waters quite as big as their Miocene forefathers. 



Although fishes had in the Eocene attained the main FISHES 

 features of their modern development, numerous new species 

 had doubtless since arisen in the various families. Not very 

 much is known on this subject, but it may be mentioned 

 that hammer-headed sharks and thresher sharks were now 

 in the ranks of the long-established non-bony fishes (Sphyrna, 



