1 8 REPTILES AND BATRACHIANS j 



Terrapins, the anterior and posterior lobes of the plastron 1 

 are movable and connected with the central part by , 

 hinges, so that their oval-shaped shell can be partly or | 

 completely closed. The mobility of the plastron varies ! 

 considerably according to species and v^ith age, for, as in the : 

 case of all Terrapins with hinged plastrons, the mobility • 

 is not so marked in the young. The species most fre- 

 quently seen in captivity are the Pennsylvanian Mud , 

 Terrapin, C. pennsyhanicum ; the Stink-pot Mud , 

 Terrapin, C. odoratum ; and the Blood-stained Mud ■ 

 Terrapin, C. cruentatum. The two former are distributed j 

 throughout the Eastern States of North America, while the ' 

 latter is confined to Central America. ; 



In C. pennsyhanicum and C. cruentatum the plastral lobes i 



are freely movable ; the plastron, however, in the former j 



species, is small, and consequently does not close up com- \ 

 pletely against the rim of the carapace, as in the case of 

 the latter. The end of the tail is provided with a horny, 

 nail-like appendage in both sexes in C. pennsyhanicum, it 



is present only in the female in C. cruentatum, and is absent j 



in both sexes in C. odoratum. In the latter species the ; 



plastron is considerably narrower and smaller than in the ' 



two preceding, and the lobes are only feebly movable, i 



This terrapin derives its name from the fact that on being •■ 



alarmed it emits from certain glands a remarkably pungent \ 



and most disagreeable odour of musk. | 



The members of this family, none of which exceed a '■ 



shell length of six inches, are found in muddy ponds or \ 



ditches, feeding on small fish and tadpoles. They are | 



very treacherous creatures ; when handled they immedi- j 



ately withdraw into their shells, firmly closing them ; they \ 



