MICKOMYS 843 



without special peculiarities ; a slightly indicated transverse 

 ridge at level of posterior border of last molar ; mesopterygoid 

 space beginning about 1 mm. behind this ridge, much narrower 

 anteriorly than posteriorly, its margins straight to tip of hamular, 

 which is barely or not in contact with auditory bulla. Mandible 

 essentially like that of Apodernus sylvaticus, but with barely 

 indicated swelling over root of incisor, more concave upper 

 margin of angular process, and coronoid more abruptly hooked 

 backward. 



Teeth. — General character of teeth much as in Apodernus 

 sylvaticus, but upper incisor perhaps a little more compressed 

 and root of lower incisor scarcely forming an appreciable 

 protuberance on outer side of mandible. Relative size of upper 

 molars more nearly as in Apodernus sylvaticus than as in 

 A. agrarius, but outline of m 1 intermediate between that in 

 these two species. Inner and outer tubercles about equal in size. 

 First upper molar with anterior crescent 

 somewhat distorted, t3 well developed 

 though closely crowded against t'2, tl some- 

 what posterior in position, the three tuber- 

 cles less contrasted in size than in the species 

 of Apodernus; no intermediate folds in 

 narrow angles between bases of tubercles, 

 but a rather well defined ridge from il to 

 inner base of tb ; t& very large, filling nearly 

 the entire space occupied by it and t9 in 



Vxc 171 



Apodernus sylvaticus; td reduced to a mere mmms ,„«„,,«„,. 

 rudiment at posterior base of tG ; postero cheek-teeth, x 10. 

 external margin of crown with slight thick- 

 ening of the enamel as in Apodernus sylvaticus ; t8 and tl showing 

 no special peculiarities. Second upper molar with first crescent 

 represented by a minute though evident t3 and a small tl ; second 

 crescent with simple tQ about equal in size to tA ; third crescent 

 with barely indicated i9 and small tl. Third upper molar much 

 as in Apodernus sylvaticus, its crown showing traces of tubercles 

 1, 4, 5, 7 and 8. Maxillary molars as in Apodernus sylvaticus, 

 but outer ledge of m 1 and m 2 slightly developed and without 

 evident cusps. 



Bemarhs. — Two well marked races are recognizable among 

 the harvest .mice of western Europe. True Micromys minutus is 

 apparently not found in this region. 



KEY TO THE EUROPEAN FORMS OP MICROMYS MINUTUS. 



Head and shoulders reddish brown, essentially 



concolor with back (England and western 



continental Europe) ■""• minutus smwinus, p. 844. 



Head and shoulders greyish, noticeably contrasted 



with reddish brown back (Hungary and Rou- 



mania) M - m. pratensis, p. 846. 



