APODEMUS 



801 



row much larger than those of the inner and outer rows, the 

 tubercles of the different rows partly joined by cross-ridges, and so 

 disposed as to form three transverse laminae having somewhat the 

 form of forwardly-bowed crescents. In each tooth this complete 

 pattern is only approximated ; in m 1 it is imperfect posteriorly, 

 in m 2 both anteriorly and posteriorly, while in m 3 it is scarcely 

 more than recognizable, For convenience of description the 

 tubercles representing the complete pattern may be numbered 

 transversely 1 to 9, beginning with the first on inner side and 

 ending with the third on outer side ; those of the inner row 

 will therefore be 1, 4 and 7, those of the middle row 2, 5 and 8, 

 those of the outer row 3, 6 and 9. Crown of m 1 more than one 

 and a half times as long as broad, its length nearly and area 

 fully equal to that of two succeeding teeth combined ; tubercles 

 of outer row slightly larger than those of inner ; anterior 

 crescent slightly distorted by the small size of tl and the very 

 broad, shallow angle between its inner border and the outer 

 border of 22 ; a small but evident projecting supplemental loop 

 usually present in angle between t3 and <2, a similar but less 

 developed loop occasionally present in that between t2 and tl ; 

 second crescent essentially similar to first, and partly or com- 

 pletely joined to it by a narrow ridge extending between t3 and 

 the outer base of *5 and occasionally a similar ridge between tl 

 and the outer base of tb, the ridges variable in development 

 though rather constant in position ; third crescent much distorted 

 by the pushing forward of <9 and tl so that the three cusps of 

 this lamina he in the same transverse line, and the re-entrant 

 angles separating them from i& and ti respectively are much 

 narrower than those behind first lamina ; t9 is broadly connected 

 with t6 anteriorly, so that the two might almost be interpreted 

 as parts of a deeply divided tQ ; tl is similarly connected with 

 <4, and, though well developed, is the most reduced cusp in the 

 tooth ; postero-external border of crown usually with a faintly 

 indicated supplemental loop, this never so well developed as in 

 Apodemus epimelas. Second upper molar sub-circular in outline, 

 its first lamina incomplete by the absence of t2 ; t3 very small, 

 terete ; second and third laminae essentially as in m 1 ; postero- 

 external loop excessively minute, though usually present in unworn 

 teeth. Third upper molar similar to m 2 in form but scarcely half 

 as large. In moderately worn condition it usually has the appear- 

 ance of a sub-circular tooth with two re-entrant angles on inner 

 side extending about half way across crown and occasionally a 

 slight notch on outer side near middle; when unworn it is 

 possible to identify tubercles 1, 4, 5 and 8, the inner re-entrant 

 angles corresponding to the spaces between first and second and 

 second and third laminae, the notch on outer surface to the 

 re-entrant angle at front of <5. Lower molars consisting of a 

 series of paired, equal, nearly distinct tubercles, each tooth 

 terminating posteriorly in a single median tubercle usually much 



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