G38 MR. W. A. FORBES ON THE UAKARI MONKEYS. [NoV. 30, 



besides an azygos lobe, which lies behind the heart in a transverse 

 direction, and is triangular in shape. The left lower lobe is the 

 largest, the right lower the next. 



The cricoid cartilage is deeply notched above. The vocal cords 

 are well developed, -35 of an inch long ; the ventricles have the 

 shape of watch-pockets, extending downwards and inwards. There 

 are no laryngeal pouches. The epiglottis is notched abov*. There 

 are about 27 tracheal rings. 



The kidneys are smooth and rather elongated in shape ; the 

 suprarenal bodies are well developed and oval. The ureters open 

 •75 inch from the neck of the bladder. 



The ovaries measure "45 inch, the Fallopian tubes 1 inch. The 

 uterus is single and smooth within; it is '75 inch long. The 

 vagina is double that length ; and the clitoris is small and flattened. 



As regards the osteology, already briefly described by Gervais 

 (" Remarques osteologiques sur les genres Brach>/nre et Oalli- 

 triche ") in Castelnau's ' Expedition dans 1' Amcrique du Sud ' [Paris, 

 18.5o, Anatomic, pp. 93-99], there is not much of interest to add. 



The vertebral ibrmula of my specimen of Brachyurus is C. 7, 

 D. 13, L. a, S. 4, C. 15 or 16'. 



Gervais gives C. 7, D. 14, L. 6, S. 4, C. 17 for B. rubicimdus; 

 the British Museum Catalogue 7, 13, C, 3, 18, for both B. calvus 

 and S. melanocephalus. In the latter skeleton ("Ouakaria spLvii," 

 BOG b) I counted, however, nineteen or twenty caudal vertebrae, the 

 first five of which bear transverse processes, whilst the terminal 

 ones are very minute and styliform. 



The carpus has an os centrale, and the humerus a well-marked 

 supracondylar foramen. The clavicles are well-developed, and strongly 

 curved sigmoidally. The manubrium sterni is broad. 



I may, however, take this opportunity of pointing out a useful 

 means of discriminating, in most cases, between the skulls of the 

 Platyrrhine and Catarrhine Monkeys, in addition to the well-known 

 differences in their dentition and in the form of their external 

 auditory meatus. 



In nearly every skull of a New-world Monkey, it will be found 

 that the parietal and malar bones are in contact with each other, for 

 a more or less considerable extent, on the side walls of the skull 

 {vide fig. 5). In the Old-world Monkeys, on the contrary, this 

 contact never (with the exception named below) takes place, the 

 frontal and alisphenoid bones articulating with each other, and so 

 cutting off the connexion between the parietals and malars {vide 

 fig. 6). In the skulls of the genus Hylobates that I have examined 

 this isthmus is very narrow, so that the parietals and malars 

 approach much nearer each other than is usually the case in the 

 Catarrhini; indeed, in one specimen in the College of Surgeons 

 Museum (5027 b) the malar and parietal of one side only touch each 



^ In my specimen the few minute terminal caudal vertebra; have imfortunately 

 been laid aside, and cannot now be found. Tliere were not, however, more 

 than three or four of them, which, added to the twelve that remain, give the 

 above number.s. 



