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. 



Hah. 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 3 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. 



Length 2 9| 



Length of palate 1 2 



from palate to occipital hole . 1 4 



Breadth at occipital ridge 1 A\ 1 2J 



at front of ear-hole 15 1 2£ 



at front of zygoma 110 1 8 



Lower jaw. 



Length 2 4 2 2\ 



Width at condyles 1 8 1 A\ 



of back part of them 11 10 



III. Arctopithecus. Bradypus, sp. Rilppell ; Pr. Max. ; 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. 



