Dr. J. E. Gray on the Genus Sternothzrus. 167 
In other specimens the front marginal shields are rather wide, 
the middle one as long as broad; the front vertebral shield is elon- 
gate, with straight sides. 
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 mys castanea of Schweigger is refer- 
able, and one of the specimens I described as S. castaneus is cer- 
tainly S. Derbianus. 
2. STERNOTHZRUS DERBIANUS. 
Pentonyx gaboonensis, A. Duméril, Arch. du 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 Duméril, in his very hasty and very incom- 
plete and inaccurate paper “‘ On the Reptiles of Western Africa,” in 
the ‘Archives du Muséum’ (vol. x. p. 165), has described and figured 
under the name of Pentony« 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 doubt 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. Duméril, who is so ready with 
and so bitter in his observations on the works of others, though his 
figure shows that the horny plates consist almost entirely of the areolee 
of the large shields, with only two or three rings of deposit round 
