CATALOGUE 



OP 



FOSSIL MAMMALIA, 



PART IV. 



Order UNGULATA. 



Suborder PROBOSCIDEA. 



In the carpus the scaphoid is supported by the trapezoid, but not 

 by the magnum, the latter supporting the lunar ; while in the tarsus 

 the cuboid articulates proximally with the distal face of the navi- 

 cular, but not with the astragalus. In both the carpus and tarsus 

 the component bones interlock but very slightly, the type of struc- 

 ture of the tarsus being one step in advance of that obtaining in 

 the Condylarthra \ The feet are plantigrade ; there are five digits 

 to each foot ; the astragalus is flat ; the femur has no third tro- 

 chanter ; the fibula articulates with the calcaneum ; and the jugal 

 forms the middle of the zygomatic arch. The brain is of large size ; 

 canines appear to be always absent ; while incisors are present 

 either in the upper or lower jaws of the males of all the forms at 

 present known 2 . The cheek-teeth 3 may attain extreme complexity ; 

 and the true molars always consist of transverse ridges, which may 

 vary greatly in height, and may be either uninterrupted, or split 

 up into inner and outer columns, which may have a more or less 



1 Vide supra, Part III. p. 172. 



2 They are rudimentary in one race of Elephas indicus. 



3 In enumerating the premolars and milk-molars of the Proboscidea, the 

 same system is adopted as in the preceding groups, the last tooth of the two 

 series being respectively termed pm. 4 and mm. 4 (see Introduction). 



PART IV. B 



