PINE-LIZARD AND ITS ALLIES: REPTILIA 357 



Of the non-poisonous snakes of. this country the little 

 green snake (Cy'elophis verna'lis) is one of the 'most interest- 

 ing and beautiful. When kept in confinement it is a harmless 

 and interesting pet. As much cannot be said for our water- 

 snakes (Tropidono'tus), which are of irritable disposition and 

 disposed to strike when handled. Blacksnakes (Basca'nion, 

 Fig. 182) have been kept in captivity and handled freely after 

 they have become accustomed to their new surroundings. 



Turtles and Tortoises. The turtles and tortoises, Chelo'nia 

 (Gr. chelone, a tortoise), are externally the best protected of 

 all the reptiles, being incased in a shell formed of plates 

 firmly fixed to the vertebrae and ribs. Chelonians have no 

 teeth, but the rim of the jaws is covered with a horny skin. 

 The limbs are sometimes modified into flippers for locomo- 

 tion in the water ; to such species the name " turtle " is com- 

 monly applied. The tortoises are land and fresh-water species, 

 with claws on the digits. 



Of the turtles, the green turtle (Ohelo'ne my' das) of the 

 warmer portion of the Atlantic, Indian, and Pacific oceans, 

 and the hawkbill (Ohelone imbrica'ta), also widely distributed 

 in warm ocean-waters, are economically important, the first 

 as -an article of food, the second as the source of tortoise-shell. 

 These turtles lay their eggs in immense numbers on sandy 

 beaches in holes dug for the purpose by the female. As 

 many as two hundred eggs may be laid by a single female. 

 Within about six weeks they hatch, having been incubated 

 by the heat of the sun. These turtles are captured by the 

 natives of different parts of the world, by diving or by nets or 

 harpoons. A peculiar method of capturing them is followed 

 by natives of such widely separated regions as Torres Strait, 

 Madagascar, and Cuba. This method consists in utilizing 

 the services of the sucking-fish (Echene'u), a commensal fish 

 provided with a sucker-like attachment on the top of the 

 head, by means of which it is borne from place to place by 



