SKELETON OF INSECTIVOEA. 



389 



254 



Skull of Bat iPhyllostoma). 



has the angle usually produced, fig. 254, A. The malleus and 

 incus are united ; the crura of the stapes are long and slender. 



The skull of the Mole {Talpa, fig. 255) is subdepressed, 

 pyriform, large be- 

 hind, tapering to the 

 fore-part, which is 

 prolonged by the 

 prenasal ossicle, n. 

 The outer surface 

 of the cranium is 

 smooth and devoid 

 of crests : it is re- 

 markable for the 

 extension of the 

 superoccipital upon 

 its upper part, and 

 for the expanded 

 mastoids. The very slender zygomata show no distinct malar 

 bones. The petrosal is largely and deeply excavated by the 

 cerebellar fossa. The rhi- 

 nencephalic fossa is large 

 and well defined. The basi- 

 occipital and basisphenoid 

 are thick and of a fine 

 spongy texture. The orbit 

 is no way defined from the 

 temporal fossa : the antor- 

 bital foramen is large. In 

 the Cape Mole ( Chrysochlo- 

 ris) the cranium resembles 

 that of the bird in its thin 

 smooth convex walls, its 

 great transverse and verti- 

 cal diameters, its allocation 

 at the back of the skull, and 

 by the transverse crest ex- 

 tending, as in some sea- 

 birds, from one mastoid, over 

 the vertex, to the other. 

 The base of the zygomatic 

 process of the squamosal is 

 deeply excavated anteriorly, and the zygomata converge, straight, 

 to the maxilla. Some Shrews {Amphisorex^ have no zygomata. 



Mole : magnified. 



