TURTLES. 443 



and introductory family Sphaegid^ contains but a single genus, which is represented 

 by a single species. 



As will be seen from the illustration, Sphargis coriacea, the trunk-back or leathery 

 turtle, is of a depressed top-shape, with the digits not separate, and those of the fore 

 limbs greatly elongated. The back differs from that of all other living turtles in pre- 

 senting no evidence of its costal origin, and the skin of the exposed portions of the 

 body is unprotected by scales. The animal is of most gigantic size, exceeding that of 

 any other member of the order ; specimens weighing over a thousand pounds being not 

 unfrequently captured. Though an animal of the widest distribution, it being found not 

 only through the temperate portions of the Atlantic, but even of the Pacific and 

 Indian oceans and the Mediterranean Sea, its habits are but little known, as it is in no 

 one locality sufficiently abundant to be profitably studied. An interesting account, 

 however, is given by an English oiBcer of a female captured in India. 



" She was captured February 1, 1862, near the mouth of the Y^ River, on the 

 sandy beach of which she had deposited about a hundred eggs, when she was surprised 

 by a number of Burmese fishermen who had been lying in ambush near the spot (a 

 favorite resort of the common turtle, Chelonia virgata), and after a desperate struggle 

 was secured. Her entire length was six feet two and a half inches. 



" The strength, aided of course by the enormous weight, of the animal was such 

 that she dragged six men, endeavoring to stop her, down the slope of the beach, almost 

 into the sea, when she was overpowered by increased numbers, lashed to some strong 

 poles, and brought into the village by ten to twelve men at a time. 



" The eggs were spherical, of IJ inches diameter, and were as palatable as those 

 of the river tortoise are nauseous. Besides those the animal had laid in the sand, there 

 must have been upwards of a thousand in her ovaria, in all stages of maturity. The 

 flesh was dark and coarse, and very few of the crowds of Burmans assembled at Ye 

 to see the animal would eat any of it." 



In 1880 a large leather-back was captured in a mackerel net off Cape Ann. It was 

 brought to the Summer Laboratory of the Boston Society of Natural History at 

 Annisquam, and from some of its flesh a soup was made, which all who partook 

 agreed was as good as that from the green-turtle. 



The family Peotostegid^ has been established to provide for an enormous sea- 

 turtle, once inhabiting the bays of the western inland seas of geological times, and 

 at present known from fragmentary fossils. 



This turtle, described as Protostega gigas, is characterized by having the protect- 

 ing shield not formed by the expansion of the ribs into a bony roof or plastron, but by 

 the development in the skin of large plates, having no sutural connection either with 

 each other or with the underlying ribs. Such fragments as have been found show 

 that the fore limbs must have been elongated and flat, like those of the sea-turtles of 

 to-day, while several other peculiarities, with this, make it quite likely that the ani- 

 mal's affinities are with Sphargis, one of the most ancient of existing turtles. 



The family Cheloniid^ includes four genera of marine turtles, all of which are 

 found along the coast of the United States. They resemble each other in having the 

 feet compressed and fin-shaped, and, as well as the neck and head, too massive to be 

 retracted beneath the shell. The carapax is so broad and flat that when the animals 

 are placed upon their backs, they are helpless, and it is never osseously united with 

 the plastron. The head is large and rounded, and covered with bony shields. The 

 animals are strong and powerful, of enormous size, and frequently lead for months at 



