2. BRADTPUS. 363 



1. CHOLffiPUS. 



Hands two-clawed ; feet three-clawed. Front grinder large, like 

 a canine. Pterygoid bone rather swollen, vesicular. 



Osteohy y.—Cuvier, Oss. Foss. v. p. 73, t. 6, 7 ; Gray, P. Z. S. 1849, 

 p. 65 ; Turner, P. Z. S. 1851, p. 207 ; Wainville, Osteogr. t. 



Choloepus, I/Iic/er, 1811 ; Gray, P. Z. S. 1849, p. 65 ; JRaj>p, Edent. 

 Bradypus, F. Cuv. Dents Mam. t. 77. 



1. Cholcepus didactyliis. (Unau.) B.M. 

 "Cervical vertebra 7; arms and claws long." 



Bradypus didactylus, Linn. 

 Bradypus unaii et Bradypus ciui, Link. 



Choloepus didactylus, Gray, Cat. Mamm. B. M. p. 192 ; Proc. Zoo!. 

 Soc. 1849, p. Go'; Turner, P. Z. S. 1851, p. 206 ; Owen, Odunt. t. 81. 

 f. 3, 4 (from Blainv.) ; Rapp, Edent. p. 4, t. 3. f. 2 (skull j. 

 Hah. Brazil and Guiana. 



2. Choloepus Hoffinaniii. B.M. 



" Cer\acal vertebra) 6 ; arms shorter ; claws short." 



Choloepus HofFmanni, Peters, Monatsb. Akad. Bert. 1858, p. 128 ; 

 Nat. Hist. Rev. 1865, p. 300. 



Hah. Porto Rico. 



Dr. Peters has described the Sloth from Porto Rico as a species 

 under the name of Choliepus Hoffrnannl (Monatsb. Berl. Akad. 1858, 

 p. 128), because it has six cervical vertebrae ; but the number of 

 the free vertebra;; in the genus appears from his own observations 

 to be variable. 



" Dr. Peters had received five skeletons of this Sloth, in all of 

 which the number of cervical vertebrae was six. In four of the spe- 

 cimens these vertebrae were all separate ; in the fifth specimen the 

 second and third had become united, as is sometimes the case in C. 

 didactylus ; and in this example, moreover, the sixth cervical had 

 coalesced with the first dorsal vertebra." — Nat. Hist. Rev. 1865, 

 p. 300. 



2. BRADYPUS. 



Hands and feet three-clawed. Front giinder small. Pterygoid 

 swollen, hollow, vesicular (P. Z. S. 1849, t. 10). Skull flattened 

 above on the forehead. 



Osteolog>i. — Cuviei-, Oss. Foss. v. p. 73, t. 4, 5, 7 ; Gray, P. Z. S. 

 1849 ; Turner, P. Z. S. 1851, p. 207. 



Brad\^ius, lUiger, 1811 ; Gray, I. c. 1849, p. GO; Rapp, Edent. p. 5. 

 ? Acheus, F. Cin\ Dents Mam. t. 78. 

 Arctopithecus, Gesner. 



" The female brought forth a yoiing one whilst in my custody ; 

 she did not carry it on her back, but in her lap. Nevertheless, 

 when the young one is older, it appears to me that the most con- 



