xin PHYLUM CHORDATA 341 



eggs, which, nearly always, like those of the oviparous Lizards, are 

 left to be hatched by the heat of the sun, some of the Pythons 

 being exceptional in incubating them among the folds of the 

 body. 



Hatteria lives in burrows in company with Shearwaters 

 (Puffinus), and feeds on Insects and small Birds. It lays eggs 

 enclosed in a tough, parchment-like shell. 



Of the Chelonia some (Land-Tortoises) are terrestrial ; others 

 (Fresh-water Tortoises) inhabit streams and ponds, while the Sea- 

 Turtles and Luths inhabit the sea. Even among Reptiles they 

 are remarkable for their tenacity of life, and will live for a long 

 time after severe mutilations, even after the removal of the brain ; 

 but they readily succumb to the effects of cold. Like most other 

 Reptiles the Land and Fresh-water Tortoises living in colder 

 regions hibernate in the winter ; in warmer latitudes they some- 

 times pass through a similar period of quiescence in the dry season. 

 The food of the Green Turtles is exclusively vegetable ; some of 

 the Land Tortoises are also exclusively vegetable feeders ; other 

 Chelonia either live on plant food, together with Worms, Insects, 

 and the like, or are completely carnivorous. All are oviparous, 

 the number of eggs laid being usually very great (as many as 240 

 in the Sea-Turtles) ; these they lay in a burrow carefully prepared 

 in the earth, or, in the case of the Sea-Turtles, in the sand of the 

 sea-shore, and having covered them over, leave them to hatch. 



The Crocodiles and Alligators, the largest of living Reptiles, are 

 in the main aquatic in their habits, inhabiting rivers, and, in the 

 case of some species, estuaries. Endowed with great muscular 

 power, these Reptiles are able, by the movements of the powerful 

 tail and the webbed hind-feet, to dart through the water with 

 lightning-like rapidity. By lying in wait motionless, sometimes 

 completely submerged with the exception of the extremity of the 

 snout bearing the nostrils, they are often able by the suddenness 

 and swiftness of their onset to seize the most watchful and timid 

 animals. In the majority of cases the greater part, and in some 

 the whole, of their food consists of Fishes ; but all the larger and 

 more powerful kinds prey also on Birds and Mammals of all kinds, 

 which they seize unawares when they come down to drink or 

 attempt to cross the stream. On land their movements are com- 

 paratively slow and awkward, and they are correspondingly more 

 timid and helpless. 



The Crocodilia are all oviparous, and the eggs, as large in some 

 species as those of a Goose, are brought forth in great numbers 

 (sometimes 100 or more), and either buried in the sand, or de- 

 posited in rough nests. 



Geographical Distribution. The order Lacertilia, the most 

 numerous of the orders of Reptiles living at the present day, is of 

 very wide distribution, occurring in all parts of the earth's surface 



