194 DR. J. E. GRAY ON THE GENUS STERNOTH^RXJS. [May 26, 



I think it better to retain the name given by Dr. Andrew Smith 

 to the Natal specimen for this species ; for it is very doubtful to 

 which of the specimens the Emys castanea of Schweigger is refer- 

 able, and one of the specimens I described as S. castaneus is cer- 

 tainly S. derbianus. 



2. Sternoth^rtjs derbianus. 



Pentonyx gaboonensis, A. Dumeril, Arch, dxi Mus. x. p. 164, t. 23. 

 f. 2 (young). 



The head very broad, depressed ; jaw dark, black-lined ; the tem- 

 poral plate single, broad and long, reaching to the back of the 

 tympanum ; the upper surface of the front leg with moderate-sized 

 scales, and with many larger, convex band scales on the inner side ; 

 the hinder edge of the fourth and the upper edge of the fifth verte- 

 bral plate tubercular ; the sternum with a deep rounded notch behind ; 

 the vertebral plate of the adult longer than broad. 



Hab. W. Africa : Gaboon ; Sierra Leone. 



Our specimens offer several varieties, thus : — 



1 . Front marginal plates thick, convex, broader than long ; the 

 front vertebral shield elongate urn-shaped. 



2. Front marginal plates as long as broad, flat ; the front verte- 

 bral shield elongate urn-shaped. 



3. Front marginal plates as long as broad, flat; the front verte- 

 bral shields elongate, with straight sides. 



In one specimen of the first variety the vertebral shields are much 

 narrower than in the other. 



The shield on the crown of the head in the two specimens which 

 have heads is more or less perfectly divided into three shields, viz. 

 one frontal and two occipital, but together they cover the whole top 

 of the head to a line with the back of the ears, and there are only 

 a few small shields between the hinder side of the hinder part of it 

 and the back edge of the temporal shields. 



I think there can be very little doubt that the specimen which 

 M. Aubrey Lecomte sent to the Paris Museum from the Gaboon, 

 and which M. Auguste Dumeril, in his very hasty and very incom- 

 plete and inaccurate paper " On the Reptiles of Western Africa," in 

 the ' Archives du Museum' (vol. x. p. 16.5), has described and figured 

 under the name of Pentonyx gaboonensis, is only the young state 

 of this species. One is surprised that a herpetologist who must 

 have unrivalled opportunities of study should not have been led 

 by the breadth of the lobes of the sternum to have doubted its being 

 a Pentonyx. However, it is well, as it gives their museum a re- 

 presentative of a species which they did not formerly possess. But, 

 what is more extraordinary still, M. A. Dumeril, who is so ready with 

 and so bitter in his observations on the works of others, though this 

 figure shows that the horny plates consist almost entirely of the areolae 

 of the large shields, with only two or three rings of deposit round 

 them, showing that the animal could not long have been hatched, yet 

 observes, " L'aspect de la carapace et sa solidite comparee a celle de 

 la boite osseuse de jeunes Pentonyx du Cap semblent prouver que 



