726 



4673. The skull of a Cebus. 



There are neither parapophyses nor mastoids. The "petrosals form slightly swollen con- 

 vexities. There is a small postglenoid venous foramen, and a second at the end of the squa- 

 mosal suture. The superoccipital plate has two large depressions. The parietals articulate 



with the malars. The dental series is entire. 



Hunterian. 



4674. The cranium of a Cebus, of larger size and with larger canines, and in which 

 the frontal is more prolonged between the parietals. The calvarium has been 

 detached, and exposes the cranial cavity. 



The petrosal has a large and deep cerebellar fossa. The tentorial margin of the petrosal is 

 sharp and slightly produced. A division of the lateral sinus excavates the sutural base of the 

 petrosal to terminate at the postglenoid fossa. The postclinoid plate is more developed than 

 in the Lemur. The rhinencephalic fossa is much smaller, and the orbital cavities form a 

 much greater prominence in the cranial cavity than in the Lemur. The foramen ovale is 

 between the petrosal and alisphenoid, and is larger than the foramen rotundum, which is mid- 

 way between it and the foramen lacerum anterius. The apex of the frontal is partially de- 

 tached as a Wormian bone. 



Mus. Sril. 



4675. The skull of a Cebus, with the permanent dentition complete. 



The small size of the hinder true molars is worthy of notice, since these are the teeth which 

 are not developed in the genus Hapale. 



Presented by Henry Cline, Esq. 



4676. The separated bones of the head of a Cebus. 



The sphenoid has no foramen ovale or foramen spinosum. The temporal differs from that 

 in the Catarhine or Old-World Monkeys by the course of the lateral sinus to the postglenoid 

 venous foramen. 



Presented by Prof. Owen, F.E.S. 



The following, to No. 4679 inclusive, are parts of the same skeleton : 



Hunterian. 



4677. The bones of the trunk, with the scapular arch, of a Cebus. 



The vertebral formula is : 7 cervical, 14 dorsal, 6 lumbar, 3 sacral, and 24 caudal. The 

 diapophysis is represented by a ridge or tubercle from the under part of the anapophysis in 

 the three last dorsal vertebrae : it projects as a distinct and large process from the lumbar 

 vertebrae. 



4678. The bones of the upper extremities. 



The internal condyle of both humeri is perforated. 



