1869.] DR. J. E.GRAY ON THE AFRICAN RHINOCEROS. 225 
and ashort hind foot like the skeleton of a human hand, with the 
short metatarsi and thumb springing from one side of the base of 
them, as if it might be opposable. 
The fingers and toes five; the fingers long, slender, the second, 
third, and fourth very long, of four joints, lower large, the last joint 
small and short; the first and third toes of three joints, the first 
strongest, the fifth shortest. The hind feet much like the human 
hand. The toes short; the thumb short, strong, from the base of 
the metatarsus, the other four toes longer, subequal, the third or 
middle toe being rather shorter, the second and fourth subequal, 
and the fifth rather the shortest and most slender. Sternal bone 
very narrow, only forming a large, oblong, elongated ring. 
See also Wagler, N. Syst. Amph. t. 5. 
DESCRIPTION OF PLATE XV. 
Fig. 1. Trionyx formosus, p. 217. 
2. Baikiea elegans, p. 222. 
7. On the Incisor Teeth of the African Rhinoceros. 
By Dr. J. E. Gray, F.R.S. 
The skull of the nearly adult female specimen of Rhinaster 
keitloa in the British Museum killed by Mr. Jesse in Abyssinia 
has the small intermaxillary bones well preserved. They are not 
united together in front; the dental edge has unfortunately been 
injured in the carriage from Abyssinia; but they each exhibit 
small cylindrical blunt rudimentary incisor teeth. The intermaxil- 
lary of the right side has a large tooth on the hinder part; the 
intermaxillary on the left side has a middle-sized tooth in the middle 
of the dental surface, and a very small rudimentary tooth behind it 
near the hinder edge of the bone. These teeth would induce one to 
believe that in the perfect state there are two, or perhaps three, in- 
cisors in each intermaxillary ; for close to the symphysis is a small 
alveolus in the front part of the dental margin on each intermaxillary ; 
but these do not now contain any rudimentary teeth. Professor Vrolik 
has described the lower incisor teeth in the skull of the young Afri- 
can Rhinoceros (see Ann. d. Sci. 1837, p. 20, t. 1B); but I believe 
that they have not before been observed in the adult animal. 
If the observations of MM. Lefebvre, Petit, and Dillon, in the 
‘Voyage en Abyssinie,’ Paris, are to be relied on, there must be 
other Rhinoceroses in Abyssinia than those we have yet seen. They 
state, “Il y a plusieurs espéces de Rhinoceros en Abyssinie. I] y en 
a qui ont deux, trois et quatre cornes: cela est certain ; il l’est moins 
qwil y en ait A cinq et six, mais on l’assure. Sur l’animal vivant 
elle est toujours mobile, sans os 4 l’intérieur ” (pp. 26, 27). 
