1 66 THE SKULL. [CHAP. 



the former ; the Lemurina, pn the other hand, more resemble 

 the lower type. 



In the Common Lemur the general proportions of face to 

 cerebral cavity, and the inclination of the occipital and 

 olfactory planes of the cranium, are quite dog-like. The 

 orbits, although completely surrounded behind by the' 

 junction of the postorbital processes of the frontal and the 

 malar, are yet perfectly continuous with the temporal fossa 

 beneath this bony bar ; that extension inwards of the 

 frontal and malar to meet the alisphenoid, and thus form a 

 posterior external wall of the orbit, so characteristic of 

 Man and all Monkeys, being absent. The lacrymal fora- 

 men, situated on the facial part of the bone, is altogether 

 external to the margin of the orbit. The os planum of 

 the ethmo-turbinal does not enter into the inner wall of the 

 orbit, but is shut out from it by the maxilla, as in most 

 inferior Mammals. The inferior surface of the tympanic is 

 developed into a large rounded bulla. The hyoid apparatus 

 much resembles that of the Dog, having the stylohyal, 

 epihyal, and ceratohyal all distinctly ossified in the anterior 

 arch, and the basihyal in the form of a narrow transverse 

 bar. 



Some of the Lemurina have much shorter faces than the 

 common species, though still possessing all the essential 

 characters of the group. Among these, Tarsius is remark- 

 able for the extraordinary size of the orbits, which are so 

 expanded that their margins form prominent, thin, bony 

 rings, and the interorbital part of the skull is reduced to an 

 exceedingly delicate septum. The orbit is also partially 

 separated from the temporal fossa as in the Simiina. 



The general characteristics of the skull of the CARNIVORA 

 have been described, as seen in the Doo;. The more 



O 



