Dr, J. E. Gray on new species of Freshwater Tortoises. ?.67 



Chelodina oblonya, may he considered as a distinct specie?, which 

 I shall proceed to shortly characterize. 



The species of the genus hitherto described have the thorax 

 covered with very thin smooth shields, so transparent that a peculiar 

 black reticulated appearance, which exists between the shields and 

 the bones of the thorax, can be distinctly seen through them. This 

 character is common to C. loayicoUis of New Holland, C. ohlonya, and 

 Mr. Collie's species from Swan River, which I propose to call, in 

 honour of my late friend and excellent collector — 



1, Chelodina CoLLiEi. 



The shield oblong, elongate, contracted and revolute on the sides ; 

 under side uniform pale yellow. 



Hah. Swan River, Aloxunder Collie, Esq. 



This species agrees with C. ohlomja in the uniform colour of the 

 back and sternum, which is only varied by the dark lines of the netted 

 appearance before referred to ; but it is easily known from that species 

 by its larger size, the much narrower shape, and the lateral margin 

 becoming strongly revolute, and the edge over the hinder limb raised 

 up and rather expanded. 



The British Museum have lately received, with some other speci- 

 mens, from the Australian continent — but unfortunately the special 

 habitat was not indicated — the shell of a Tortoise which has all the 

 characters of the genus as at present defined, except that, instead of 

 the shields on the thorax being thin, submembranous and semitrans- 

 parent, they are thick, horny and concentrically grooved like the 

 shields of many other genera. It is not accompanied by the head or 

 limbs of the animal, so we have not the means of determining if 

 they offer any characters which, with the peculiar structure of the 

 shell, might render it desirable to form it into a separate genus. 

 It may be defined and thus named : — ■ 



2. Chelodina sulcata. 



Shell depressed, roundish ovate, brown ; shield horny, thick, 

 distinctly concentrically grooved. 

 Hah. Australia. 



Fam. III. Trionycid.e. 



The species of this family, which have the hind legs covered with 

 moveable flaps aflixed to the sides of the hinder lobe of the sternum, 

 named Cryptopus by MM. Dumeril and Bibron, may be diWded 

 into two very distinct geographic genera, 



1. Emyda, Gray. 



The margins of the upper shield strengthened with bones ; the 

 sternum with three pairs of callosities and a small odd one behind 

 the anterior pair. Asia. 



2. Cyclanosteus, Peters. 



The margin of the upper shield flexible, without any bones ; the 

 sternum with four pairs of callosities and an odd one behind the two 

 anterior pairs; the pair on the hinder lobes small, far apart. Africa. 



