729 



4689. The skull of an immature Spider-Monkey (Ateles). 



The permanent canines and last true molars have not come into place. The paroccipitals 

 and mastoids form rough tubercles, but do not extend downwards as processes. The carotid 

 arteries perforate the back part of the petrosals. There is a venous foramen at the suture 

 between the squamosal and alisphenoid. The vomer extends to the posterior nares. The in- 

 cisive foramen is large and single. 



Hunterian. 



4690. The skeleton of a Spider-Monkey (Ateles paniscus). 



The vertebral formula is : 7 cervical, 13 dorsal, 4 lumbar, 3 sacral, and 30 caudal, but the 

 latter series is incomplete. The postzygapophyses of the thirteenth dorsal indicate, by the 

 inexactness of their adaptation to the prozygapophysis of the next vertebra, that one may be 

 omitted in this artificially articulated skeleton. The humerus is imperforate at its distal end. 



Mus. South. 



The following, to No. 4716 inclusive, are parts of the same skeleton of a Spider-Monkey 

 {At eles paniacus) : 



Hunterian. 



4691. The cranium, with the calvarium detached. 



It shows the same venous foramen formed by the meeting of two converging sinuses between 

 the squamosal and alisphenoid. Ossification has extended into one half of the tentorium. 

 The cerebellar fossa in the petrosal is of great depth. The foramen ovale is formed by the 

 petrosal and alisphenoid. 



4692. The lower jaw. 



The symphysis is completely anchylosed, and the angle of the jaw rounded off. The con- 

 dyles and small coronoid processes are of equal height. 



4693. The atlas. 



The transverse process is perforated vertically, and the neural arch transversely, by the 

 vertebral artery. 



4694. The axis. 



The pleurapophysial ridge of the transverse process is produced obliquely downwards. The 

 neural spine is well developed, and supports upon its upper surface a vertical ridge. 



4695. The third to the sixth cervical vertebrae inclusive. 



They show the anterior concavity and posterior convexity of the articular ends of the cen- 

 trums in the transverse direction, and their anterior convexity and posterior concavity in the 



5 A 



