172 Merrlam — Descriptions of Nine New Mammals. 



Cranial and Dental Ch(iraeter><. — Hkull resembling that of Are l- 

 eola iia);/()Uonensls in general form and in the vertical expansion 

 of the middle part of the zygomatic arch and the deflection of 

 the short nasals. The incisive foramina are a little more than 11 

 times tlie length of the itremaxillary symphesis ; the audital 

 bulUe are large and smoothly rounded ; the last upper molar has 

 two lateral closed triangles on its outer side, and the first lower 

 molar has 3 lateral closed triangles on the inner and two on the 

 outer side as in typical My nomes, hut the middle upper molar 

 has no trace of the postero-lateral» loop characteristic of the 

 members of that section from the eastern part of North America. 



(renus Sorex. 



No shrew of the restricted genus Sorex has been heretofore 

 known from Mexico, though a single S2")ecies has been descriljcd 

 by Alston from Coban, Guatemala. It is of special interest 

 therefore to record the fact that INIr. Nelson had the good fortune 

 to secure specimens of two species on the north slope of the 

 lofty Sierra de Colima, in Jalisco, neither of which appear to 

 have 1)een described. 



One of these, which I have named Sorex oreopolas, was found in 

 Arrieola runways in grassy places at an altitude of 3,050 meters 

 (10,000 feet) ; the other, here named Sorex snussurei, was captured 

 at the base of a rocky ledge in a sheltered caiion at an altitude 

 of aliout 2,410 meters ((S,000 feet). The latter species may be 

 readily distinguished from the former l\y its much longer ears 

 and tail, Ijy the color of its under parts, and by cranial propor- 

 tions. In the relative size of the lateral unicuspidate teeth both 

 of these shrews resemble Sorex dohwai from tlie Saw Tooth 

 mountains of Idaho, though the height of the teeth is much 

 less.* The first and second upper unicuspids are subequal ; the 

 third and fourth likewise are su])eiiu*il and about half the size 

 of tlic first and seccjnd ; the fifth is in the tooth row and dis- 

 tinctly visil)lc from tlie outside, but is consideraldy smaller in 

 S'liissarei than in oreopolas. 



Three s])ecimens of S. oreopolas and two of *S*. snussureL were 

 obtained. They may be known from the following descriptions : 



*See North Ainerinui Kauna, No. 5, 1891, p. oo. 



