230 Zoological Society. 



Lower jaw not produced on the upper edge between the teeth, but 

 slightly keeled in front of the chin . 



Face with a black streak from the back angle of the eye. 



Cuvier, Oss. Foss. v. t. 4, figured the skeleton, and t. 5, the skull 

 and bones of the feet of this genus ; the skull is copied R. A. Illust. 

 t. 70. f. 1 a. Wiedemann, Arch. Zool. mid Zoot. i. t. 1 and 1*, and 

 Spix, Cephal. t. 7. f. 12, figure the skull, and Blainville figured two 

 skulls belonging to this genus in his ' Osteogra[)hia.' 



In the young skull there is sometimes a slight projection on the 

 front edge of the zygomatic arch, assisting to form the back edge of 

 the orbit, but this process seems soon to disappear as the animal 

 increases in size, and I have not found it in any of the older skulls. 



Cuvier, Desmarest, and most French authors, have considered all 

 the individuals of this genus as belonging to one species, and have 

 given an indefinite description, so as to include them. Cuvier (Reg. 

 Anim. ed. 1. 217) thus describes that species : " Sa couleur est grise, 

 souvent tachetce sur le dos de brun et de blanc : plusieurs indi\ddus 

 portent entre les epaules une tache d'un fauve vif que traverse une ligne 

 longitudinale." He refers for the species to both Bufon' s Jiffures, 

 xiii. t. 5 & 6. In the second edition he remarks, "On connait un 

 Ai dit la dos bru/S, parce qu'il a entre les epaules une tache noire en- 

 touree de fauve ; ce n'est selon M. Temminck, qu'une variety resultant 

 de C2 que des longs poils de ses epaules sont uses." — Cuvier, Reg. 

 Anim. ed. 2. p. 225. 



Desmarest describes it in nearly the same words, but he notices 

 four varieties, including amongst them B. crhiitus (var. c.) ; the spe- 

 cial description of the species and var. b. appear to be A. gularis ; 

 var. a. appears to be from a female, and var. d. from a male of A. 

 Jlaccidus. 



Knorr (Delices, i. 97. t. K. f. 3) figures the foetus of a species of 

 this genus. 



a. Fur moderately rigid ; the back lohite-spotted ; dorsal streak 



elongate. 



1. ArCTOPITHECUS GULARIS. 



Dark grey-brown ; back white varied, with an elongated black 

 streak, with a broad patch of ^oft yellow hair on each side between 

 the shoulders. Skull with a broad forehead, rather convex over the 

 back part of the orbits. The upper front grinder rather large. The 

 hinder side of the lower jaw concavely cut out, and with the lower 

 Jingle slender and acutely j)roduccd ; front of the lower jaw flat, not 

 keeled up the suture. 



Bradypus gularis, Riippelh Mus. Senckenh. iii. t. 11. 



Ai a dos brule, Bufon, Hist. Nat. xiii. 62. 



Ai adult. Biff on, Hist. Nnt. xiii. t. 6. 



B. tridactylus, Griffith, A. K. iv. 271. 



B. tridactylus, description and var. b. Desni. Mainm. 



D'Ai B. tridactylus, var. Cuvier, R^g. Anim. Ilhist. Mainm. t. "0. 

 f. 1. 



