400 



A MANUAL OF DENTAL ANATOMY. 



the milk dentition is tolerably complete, while in the 

 Shrews it has all but, or quite, disappeared. 



The W-pattern characterising the molars of Insectivora 

 has already been alluded to ; it is well exemplified in the 

 molar of Urotrichus. 



In this tooth, as has been clearly shown by Prof. Mivart 

 (Osteology of Insectivora, Journ. of Anat., 1868), the four 

 cusps of the typical teeth (a, I, c, d) have been added to 

 by the elevation of the cingulum into three or four external, 

 and one internal cusp, making up the total number to nine. 

 Thus it is that the molars of this order often fairly bristle 

 with cusps. 



In the Mole the number of cusps is diminished by the 

 coalescence of b and d into a ridge, and the disappearance of 

 FIG. 176 ('). 



l'' \3|T ** \jii^r' a 



1> I" 



AFC 



the inner cusp of the cingulum, while the simplification is 

 carried yet further in the Cape Mole (c in Fig. 176). 



It would be impossible to notice the somewhat varied 

 dentitions of other Insectivora in these pages, but mention 

 must be made of the very anomalous teeth of the Galeo- 

 pithecus, formerly placed with the Lemurs under the title of 

 "Flying Lemur." 



Its lower incisors are divided by a number of vertical 

 divisions running down through a great part of the length 

 of the crowns, so that they can be compared to combs, or to 



(*) A. Upper molar of Urotrichus ; B. Mole ; C. Cape Iridescent Mole, 

 (Cbrysochloris). 



