141) DR. J. " 'VY** ON THE BRADYPODIDvE. [May 2, 



examine aud describe them osteologically ; uot that I in the least 

 underestimate the value of this very interesting and important branch 

 of science ; but the theory of the structure of the skeleton has very 

 little to do with the zoological distribution, and, to judge by the 

 results, a scientific man who has paid great attention to that study 

 may have a very imperfect idea of the value of the zoological cha- 

 racter afforded by the skull as a whole, and most crude ideas of the 

 connexion of the genera with oue another, even iu examining the 

 perfect skeletons of living animals ; indeed such ideas make one 

 lose all confidence when the same kind of study is applied to fossil 

 remains. I need only refer to the extraordinary mistakes that have 

 been made iu naming the skulls of such large animals as Crocodiles, 

 Rhinoceroses, Tapirs, and Cetacea by one of the most celebrated 

 osteologists, iu which he has given the same species various names 

 and included under the same name several most distinct species ; 

 and if this be the case where perfect specimens are to be examined, 

 what must we expect of multitudes of genera established on small 

 fragments found in a fossil state, or of the affinities they are said 

 to present. Paleontology, as it is called, will never be worthy the 

 name of science until the paleontologist has a good knowledge of 

 recent species and their characters, and the bones of the recent and 

 fossil species are studied together. 



I. Fur moderately long and rather rigid, dark grey ; back with a 

 dorsal streak and distinct white spots. Males with a large 

 yellow patch of soft hair on the buck. 



a. Forehead, cheeks, chin, and throat with short, erect, rigid, yellow 



hair. 



1. Arctopithecus cuculliger. The Yellow-throated Ai. B.M. 



Forehead, temple, chin, and throat covered with short, erect, yel- 

 low hair, surrounded by a more or less broad black collar ; spot 

 behind the eye small ; fur blackish, short, rigid; under-fur short, 

 sparse. Skull : uose rather elongate, narrow ; lower jaw moderately 

 strong ; the front lower grinder flat, smooth, and moderately broad 

 iu front ; angle of the lower jaw much produced, slender, elongate. 



c? and 2 • Bradypus cuculliger, Wagler, Isis, 1831, p. 605; and 

 Wagner, iv. p. 145? Rapp, Edentata, v. t. 3. f. 1 (skull). 



Bradypus tridactylus guianensis, Blaiuville, Osteog. t. ii. fig. 



Arctopithecus gularis (part.), Gray, Cat. Edentata, p. 364 ; P. Z. S. 

 1849, t. xi. f. 6 (angle of lower jaw). 



$ . Blackish ; shoulders, back, and haunches covered over with 

 close large black spots. The head aud throat yellow. 



Young. Fur long, soft, and flaccid, grey-brown ; back whitish, mot- 

 tled ; face and throat yellowish ; eye-streak and circumference of 

 head and neck blackish. 



Hub. Guiana (Riippell) ; Demerara, Brit. Mus. 



Wagner says this species has no postocular streak ; but this does 

 not agree with our specimen. The fur of the female in the Museum 



