Zoological Society. . 229 
- The skull above described was taken from the skin of a specimen 
in the British Museum. We have also a skeleton of a second speci- 
men, which was received from M. Becker under the name of Brady- 
pus torquatus, from Brazil. 
2. BRADYPUS AFFINIS. 
Fur unknown. 
The forehead of the skull rather convex, with a slight convexity 
over the orbits and a higher convexity over the front part of the tem- 
ples. The occipital ridge very concave and rather narrow. The ptery- 
goid bones rather swollen, rather compressed on the sides, and mode- 
rately thick. The lower jaw with a broad, gradually tapering, trun- 
cated process in front between the teeth; the sides rather curved, 
simple-edged beneath; the angle broad, acute, slightly produced 
beyond the back edges of the condyles. The lower process of the 
zygoma slender, tapering. Teeth moderate, the lower front one much- 
compressed, transverse, linear. 
Hab. Tropical America. 
The skeleton from which this skull has been described was received 
by the British Museum from M. Brandt, under the name of Bradypus 
torquatus, from Brazil. 
It has been suggested that the two skulls in the Museum which 
have been extracted from skins of Bradypus crinitus, may both belong 
to male or female animals, and that the skull here described may 
belong to the other sex. As this is a matter of doubt which can only 
be settled by the examination of more specimens the sexes of which 
are known, I have considered it desirable that the skull should be 
figured and described. I may remark that the form of the hinder side 
and angle of the lower jaw of all the three specimens of these skulls 
are very similar. 
Skull. B. torquatus. B. affinis. 
in. lin. in. lin. 
ere ley rete Reere Biel « gle cin ax wietsys 2 9f 
henoth, of palate Lire. osc ete | Sr 
from palate to occipitalhole. 1 4 
Breadth at occipital ridge........ 1 44 1 23 
— at front of ear-hole ...... eo 1 22 
— at front of zygoma ...... Pe PS 
Lower jaw. 
12 1 ee ae SEE SOI 2 4 2 24 
Width; at condyles. sii... ae ape n - Eu.8 1 4% 
of back part of them ...... Or Ft 0 10 
III. ArcropitHecus. Bradypus, sp. Riippell; Pr. Mazx.; Cu- 
vier, Oss. Foss.; Blainv. Acheus, F. Cuvier, Dent. Mamm. t. 78. 
Tardigradus, sp. Brisson. 
Hands and feet three-clawed. Skull rounded above on the fore- 
head. Grinders: front upper very small, cylindrical; front lower 
smaller than the others, subcylindrical. Pterygoid separate, com- 
pressed, erect, thin, simple. Intermaxillaries none. 
