26 CHELONIA. 



each sternal plate with a large square black spot ; lower parts of the marginal plates uniform 

 yellow, without spots or ocelli. Head greenish olive, with a yellow band commencing from 

 behind the eye. 



For the determination of this species I had a coloured drawing, made by Dr. Cantor at 

 Chusan, and kindly communicated to me by Mr. F. Moore, Gustos of the East India Collection, 

 to which the drawing belongs ; and two specimens from Chusan — one in the British Museum 

 (K nigricans, spec, a. Gray, Catal. Shield Kept. p. 21), and one in the East India Collection ; 

 both specimens agree perfectly with each other, and the latter is without doubt the typical 

 specimen from which Cantor has figured the species. It differs so constantly from E. nigri- 

 cans in the shape of the nuchal and of the sternal plates, in the depressed shell, and in the 

 coloration, that we cannot consider them as identical. The shell of the larger specimen is 

 5 inches long and 4 inches broad. 



Emys nigbicans. The Blackish Pond Tortoise, 



Emys nigricans, Gray, Proc. Zool. Soc. 1834, p. 53, and Shield Rept. p. 20. tab. 6. 



Two specimens of E. nigricans are preserved in the British Museum ; the first (typical) 

 specimen is a shell, 4 inches long, and injured behind: a peculiarity of this specimen (which 

 has been figured by Dr. Gray) is the absence of a nuchal plate. The second specimen is a 

 stuffed animal, the shell of which is a little larger than that of the fii'st ; it has a nuchal 

 plate. We take our description from the second specimen. 



Form. — Shell rather elevated along the median ridge, which is very distinct, and extends 

 fro7n the nuchal to the end of the last vertebral plate ; no costal ridge, only the centres of 

 the areolae are a little elevated. The upper shell has a very slight notch anteriorly and pos- 

 teriorly, and is scarcely serrated ; its lateral margins are somewhat reverted. The sternum 

 is a little wider between the axillary incisions than between the inguinal, its width being 

 one-half of its length ; it is truncated anteriorly. 



Plates. — ^The areolae are distinct, situated on or near the posterior margins of the plates. 

 Nuchal flate very narrow [sometimes absent). Vertebrals subimbricate : the first pentagonal, 

 broader than long, broader anteriorly than posteriorly ; the last with the keel very distinct, 

 and broader than the caudals ; caudals broader than long. Gulars rather broader than long ; 

 postgulars rather shorter than pectorals ; the sternal portion of the abdominal square, but 

 shorter than the prceanal ; the sutui-e between the anals as long as their hind margins, which 

 meet at a right angle. 



Head proportionate ; jaws not denticulated. Tail of moderate length. Feet broadly 

 webbed ; forearm with large, thin scales. 



Colour. — Shell brown ; sternum yellow, marbled with black near the margins ; head and 



