732 



4716. The left fibula, longitudinally bisected. 



4717. Portions of the upper and lower jaws of a Spider-Monkey (Ateles). 



The whole of the permanent dentition is included in the lower jaw, and the mode of im- 

 plantation of these teeth is exhibited on the right side of both jaws. 



Presented by Prof. Owen, F.1LS. 



Genus Mycetes. 



tl i 1 e 1 22 1 



Dental formula : z ^, c , 



4718. The skull of the Red Howling-Monkey (Mycetes seniculus). 



The dentition is entire. An obtuse paroccipital ridge extends from the condyle to the 

 mastoid ridge. The precondyloid, jugular, and carotid foramina all open into an irregular 

 fossa between the petrosal and paroccipital ridge. There is a small venous foramen outside 

 the mastoid, and a second at the anterior border of the squamosal. The superoccipital region 

 is almost flat and vertical, at right angles with the parietal surface, from which it is sepa- 

 rated by a well-defined ridge. The suture between the frontals and that between these and the 

 nasals are obliterated, together with the coronal sutures. The maxillo-premaxillary sutures 

 remain, and demonstrate the junction of the premaxillaries with the nasals. The chief feature 

 of peculiarity in the skull of the Howler is the extraordinary depth of the mandibular rami, 

 especially of their angular and ascending portions. This development relates to the pro- 

 tection and support of the still more extraordinarily developed hyoidean and laryngeal appa- 

 ratus the organs of the loud and dissonant cries which have procured for these South Ame- 

 rican Monkeys their common name. The superior length of the postglenoid process, in 

 relation to the larger and heavier lower jaw, is worthy of notice. The ectopterygoids much 

 exceed the entopterygoid plates in size. 



Mus. Langstaff. 



Section CATARHINA. 



The following dental formula obtains throughout the whole of this group : 



J 2 ~2 1-1 n 2-2 3-3 _ 



1 2 _ 2 > C 7=1> P 22' m 3-3 6 *" 



(With a narrow sternum.) 



Genus Papio. 



4719. The skeleton of a male Mandrill (Papio Mormon}. 



The vertebral formula is : 7 cervical, 1 2 dorsal, 6 lumbar, 4 sacral : there are 9 caudal, 

 but one or two may be wanting. The transverse process of the atlas is perforated lengthwise 



