510 ZOOLOGY. 



the carotis cor, and subclavian artery of the same side. The 

 veins are two in number, as they enter the lieart : 1st. The 

 pulmonary veins (pv) unite to form a very short trunk 

 emptying into the left auricle ; while (2d) the two venos 

 cavcB supcrm-es unite with the cava inferior ( V) to empty 

 through the sinus venosus into the right auricle. 



The kidneys lie at the posterior end of the body against 

 the vertebral column. In the figure they are concealed by 

 the bladder and oviducts. (Minot.) 



Tliere are alxjut forty species of Ohelonians in America 

 north of Mexico. The lower forms of turtles are the marine 

 species. Such is the great sea-turtle {Sphargis coriacea 

 Gray) of the Atlantic and Mediterranean, which is the 

 largest of all existing turtles, and is sometimes eight feet 

 long, weighing from eight hundred to twelve hundred pounds. 

 Next to this species is the loggerhead turtle [Thalassoclielys 

 crwuaiia Fitzinger), which is sometimes seen asleep in mid- 

 ocean. Still another is the hawk-bill or tortoise-shell turtle 

 [Eretmochelys imbricata Pitz.), the jDlates of whose shell is 

 an article of commerce. The green-turtle of the West 

 Indies weighs from two hundred to three hundred pounds, 

 and is used for making delicious soups and steaks ; being 

 caught at night when laying its eggs on sandy shores. All 

 the foregoing species have large, flat, broad flippers or fln-like 

 limbs, while in the pond and river turtles the feet are webbed, 

 and the toes distinct. A very ferocious species is the common 

 soft-shelled turtle {Aspidonectes spinifer Lesueur), whose 

 shell is covered with a thick leathery skin. It is carnivorous, 

 voracious, living in shallow muddy water, throwing itself 

 forward upon small animals forming its prey. The snap- 

 ping-turtle [Ghelydra serpentina Schweigger) sometimes 

 becomes five feet long ; its ferocity is well known ; the flesli 

 makes an excellent soup. 



The terrapins belong to the genus Pseudemys ; the pretty 

 painted turtle [Chrysemys picta Agassiz) is common in the 

 Eastern States, while the Nanemys guttatus (Agassiz), or 

 spotted tortoise, is black, spotted with orange. In the land 

 tortoises the feet arc short and stumpy. The Teshido Tndica 

 of India is three feet in length. The great laud tortoises of 



