1 8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 60 



Measurements. — Type: Total length, 98 mm.; tail vertebras, 31; 

 hind foot, 12.5. Average of two adult topotypes : 96 (91-101) ; 

 26.5 (25-28) ; 12.2 (12-12.5). Skull (type) : Condylobasal length, 

 18.8 ; zygomatic breadth, 6.5 ; lachrymal breadth, 5 ; breadth of brain- 

 case, 9.3 ; depth of brain-case, 5.1 ; upper tooth row, 8.8. 



Remarks. — By the discovery of this small species so close to the 

 Colombian frontier, the known range of the mexicana group is ma- 

 terially extended eastward from Costa Rica. It seems to require 

 close comparison only with orophila. The skull differs conspicu- 

 ously from that of typical mexicana in narrower brain-case, and in the 

 weaker development of the inner cusps of most of the upper teeth ; 

 the postero-internal lobes of the first and second upper molars are 

 lower and unpigmented much as in tropicalis. The claws of both 

 fore and hind feet are unusually small for a shrew of the mexicana 

 group. 



Specimens examined. — Three, all from 4,500 to 5,000 feet alti- 

 tude along the headwaters of the Rio Limon in the vicinity of Mount 

 Pirri. 



