1. PLATYSTKRNUM. 



47 



Carapace much deprossefl, oval, with a feeble median keel poste- 

 riorly ; anterior border broadly cmarpinate. Nuclial shield very 

 small, broader than long; vertebrals broader than long, as broad as 

 or a little narrower than the costals, much broader in the young, 

 in which the posterior border of the carapace is distinctly serrated, 

 I'ront lobe of plastron squarish, posterior angularly emarginato ; the 

 width of the bridge contained four or five times in the length of the 

 plastron ; the longest plastral shields are the anals, the femorals, 

 and the humerals ; the shortest, the gulars, Avhich occupy, however, 



ViiT. 14. 



Shell of Tlatysternum megace'phalum. 



the whole width of the front border of the plastron ; frequently a 

 small intergular shield between the gulars and the humerals. Upper 

 surface of head and temple with an undivided horny scute. Throat 

 with round flat tubercles. Anterior face of arm with large squarish 

 scutes. Hinder side of thighs with large conical tubercles. Tail at 

 least as long as the shell. Carapace and soft parts of adult olive- 

 brown ; plastron yellowish brown. Young more elegantly marked: — 

 Upper surface of head and neck and carapace olive-brown, with a 



