THE LAND TORTOISES AND TERRAPINS 



2429 



Hamilton's 

 Terrapin 



UPPER SURFACE OF CARAPACE OF 

 HAMILTON'S TERRAPIN. 



The handsomely-colored Hamilton's terrapin (Damonia hamiltoni) 

 from India, conspicuous for its black and yellow, highly vaulted, and 

 three-keeled carapace, is the best-known representative of a third 

 genus, distinguished from the foregoing by the 

 hinder aperture of the nostrils opening behind 

 the line of the eyes, and the great breadth of 

 the palate. Like the two preceding genera, the 

 entoplastral bone of the plastron is traversed by 

 the groove formed by the union between the 

 humeral and the pectoral shields; and the hinder 

 part of the head is covered with small shields. 

 Hamilton's terrapin has the elevated carapace 

 marked with three interrupted longitudinal keels, 

 or rows of nodose prominences; the color of the 

 shell being dark brown or blackish, upon which 

 are spots and streaks of yellow, and the soft parts 

 having likewise a similar coloration. While in 

 young individuals the hinder border of the 

 carapace is strongly serrated, in the adult it be- 

 comes nearly smooth. This species attains a length 

 of nearly nine inches at the present day, but fossil 



examples found in the Pliocene rocks of Northern India were still larger. These 

 fossil specimens lived with numbers of mammals belonging entirely to extinct spe- 

 cies. There are four other species of the genus ranging over Malayana, Southern 

 China, and Japan. 



The last representative of the group with a smooth palate and 

 carnivorous habits is the North American genus Malaclemmys, distin- 

 guished from the last by the head being covered with continuous skin, 

 and by the groove formed on the plastron by the junction between the humeral and 

 pectoral shields being situated in advance of the entoplastral bone. While two of 

 the species inhabit the valley of the Mississippi, the salt-water terrapin (M. terrapin') 

 is a frequenter of the salt marshes of the Atlantic coast. The latter has an oval 

 and much depressed carapace, which attains a length of nearly seven inches, and is 

 characterized by the great width of the first and second vertebral shields; its gen- 

 eral color being either olive, with black concentric lines, or uniform blackish. The 

 plastron is yellowish or reddish, with variable black markings. 



It is this species that generally forms the celebrated New York dish known as 

 terrapin; but it would seem that other species are also used, as the following 

 account refers to terrapins taken high up the rivers. The best terrapins go by the 

 name of "diamond backs," and do not generally exceed some seven inches in 

 length, although they may rarely measure as much as ten inches, but all terrapin 

 of larger dimensions belong to the inferior kinds, ordinarily designated ' ' sliders. ' ' 

 According to Mr. W. M. Laffan, " terrapin are caught all the way from Savannah 

 and Charleston to the Patapsio river at Baltimore, but the genuine diamond back 

 belongs only to the Upper Chesapeake and its tributaries. The majority of the 



Salt-Water 

 Terrapin 



