90 



INSECTIVOBA 



FIG. 18. 



Croeidura leucodon. Anterior 

 teeth in profile. X 5. 



triangular, its height less than half that of main cusp and only 

 a little more than half that of first unicuspid tooth. General 

 form of first incisor not unlike that of 

 Neomys fodiens, but with even more 

 contrast between height of the two 

 cusps. Anterior lower incisor simple, 

 rather robust, the shaft slightly taper- 

 ing, the point slightly bent upward, the 

 cutting edge without lobes. Upper 

 unicuspids robust, strongly contrasted 

 in size. First about double the height 

 of second and third, the points of which 

 are nearly in line with that of basal 

 lobe of anterior incisor. Its crown is 

 somewhat longer than broad, with main 

 axis slightly oblique to that of tooth-row. In lateral view it is 

 nearly triangular, with anterior border about half as long as upper 

 and lower. Cutting edge essentially 

 as in Neomys, but better developed 

 and reaching posterior border of 

 tooth somewhat outside of middle. 

 Crushing surface well developed, 

 occupying about one-third area of 

 crown. Second and third unicus- 

 pids approximately equal, in both 

 height and crown area, to basal 

 lobe of anterior incisor, their crowns 

 distinctly narrower as well as much 

 shorter than that of first 

 unicuspid, their cutting 

 ridge and crushing sur- 

 face less well differen- 

 tiated than in first. 

 Second smaller than 

 third, its crown about 

 as broad as long. Third 

 separated from large pre- 

 molar by a slight space, 

 its crown longer than 

 broad, its cusp about 

 equal in height to para- 

 cone of large premolar. 

 Lower unicuspids essen- 

 tially alike in form, the 

 second differing from that 

 of Sorex and Neomys in 

 the complete absence of the rudimentary second cusp. First low, 

 narrow and long ; second high, its crown about as broad as long. 

 Upper cheek-teeth with crowns narrower than in Sorex and 



Fig. 19. 

 Croeidura leucodon. Teeth X 10. 



