2G6 Zoological Society : — 



confounded together by the American naturalists, or have been moat 

 unaccountably overlooked. They may be thus defined : — 



1. ArOMOCHELYS ODORATA. 



Head moderate, with two streaks from the nose, one above and 

 the other under the eyes, to the side of the neck ; the back oblong- 

 convex, the vertebral line rather flattened ; the gular plate small, 

 triangular, the humeral plate rather oblique, shield brown, purple- 

 brown sjiotted. 



Ilolbrook, N. Amer. Ilerpet. t. 22. 



Ilab. Uuited States and Louisiana. 



2. ArOMOCHELYS CARINATA. 



AVe have four specimens of this species in the Museum Collection. 

 Cat. Tortoises B.M. t. 20 a. 



Head very large, black-dotted, without any lateral streaks ; back, 

 oblong, very high, the vcrtcbr.il line high and acutely keeled the 

 whole length, shields grey-brown, spotted and lined with j)urple- 

 browu ; the gular j)late very small, linear, transverse marginal, the 

 humeral plate square, transverse, i)arallel to the pectoral plates. 



Hab. North America, Louisiana. 



There are two species of North American Tortoises which are re- 

 ferred to the genus Chelydra, which are so differently organized 

 that they are evidently the types of two very distinct genera, which 

 may be thus characterized : — 



1. Chelydra. 



Head moderate, rather depressed, covered with a soft skin, chin 

 bearded, neck granular ; back with two slight keels; marginal plates 

 in a single series. 



Chelydra serpentina. 



2. Macrochelys. 



Head large, angular, contracted in front, covered with symmetrical 

 homy plates, neck with several series of spinose warts ; back with 

 three sharp continued tubercular keels ; the lateral marginal plates 

 in a double series. 



M. Tetnminckii. 



Fam. IL Chelwidm. 



When Australia was first visited by Sir Joseph Banks, he brought 

 home with him from New Holland a freshwater Tortoise, which iJr. 

 Shaw described under the name of Testudo lonyicollis. This has 

 been made the type of the genus Chelodina. Recent travellers in 

 Australia have shown that the genus is distributed over the country; 

 each part appears to have a species peculiar to itself. In Capt., 

 now Sir George Grey's Travels, 1 described and figured a species from 

 Western Australia under the name of Chelodina ohlonyu. In a col- 

 lection which we have lately received from Ilaslar Hospital, there 

 are two very large specimens of the genus sent from Swan River 

 bv the late Mr. Collie, wliich, though similar in several respects to 





