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NORTH AMERICAN FAUNA. 



[No. iO. 



General remarJcs. — The only Shrews that resemble aS'. saussurei exter- 

 nally are its subspecies caudatus and ;S'. maerodon, from both of which 

 it differs in greater length of tail and paler color of under parts. 



Sorex saussurei is an exceedingly interesting type, inhabiting, either 

 in its typical form or as subsi^ecies caudatus, most of the higher moun- 

 tains of southern Mexico, from the volcano of Colima on the west to 

 Mount Orizaba on the east. On mapping the distribution of the typical 

 form and the subspecies separately, it is found that the former inhabits 

 the mountains whose watershed finds its way to the Pacific, while the 

 latter is confined to those on the Atlantic slope. Specimens from Cerro 

 San Felipe, Oaxaca, on the border land between the two, are interme- 

 diate in characters. 



Specimens examined. — Total number, 24, from the following localities: 



State of Jahsco : North slope of Sierra Nevada de Colima, 2. 

 State of Michoacan : Nahnatzm, 5. 



State of Mexico: Mount Popocatepetl, 2; Salazar, 2; North slope of volcano 

 of Toluca, 1. 



State of Morelos: Tetela del Volcan, 1. 



State of Oaxaca: Mountains 15 miles west of Oaxaca City, 1; mountains near 

 Ozolotepec, 4 ; Tlapancingo, 2 ; Tamazulapam, 2. 



State of Guerrero: Mountains near Chilpancingo, 2 (not typical). 



SOREX SAUSSUREI CAUDATUS subsp. uov. 



Typeivom. Reyes, Oaxaca, Mexico (altitude 10,200 feet). Type, No. 69600, $ yg, ad., 

 U. S. Nat. Mus., Dej^artment of Agriculture collection. Collected October 21, 1894, 

 by E. W. Nelson. Original number, 6963. 



General characters. — Similar to 8. saussurei, but tail much longer 

 (averaging 57 instead of 47 mm.); hind foot slightly longer j color of 

 under pa-rts darker. 



Color. — Upper i)arts finely mixed sepia and blackish j under ijarts 

 seal brown, i^assing insensibly into the color of the back; feet and tail 

 blackish, the latter fading to brownish underneath. 



Cranial and dental Skull and teeth similar to those of 



saussurei, but averaging slightly larger, w-ith brain case somewhat 

 higher. Thii d unicuspidate tooth slightly smaller than fourth. 



When good series of skulls are available from single localities (as 

 from Eeyes and Mount Zempoaltepec) it is found that two types exist 

 in each: (1) A large skull with high brain case, large m^ (with squarish 

 body), long unicuspidate row, the anterior teeth of which are not 

 markedly swollen; and (2) a slightly smaller skull with flatter brain 

 case, smaller m^ (with narrower body and rounded angles), shorter uni- 

 cuspidate row, the first and second teeth of which are conspicuously 

 swollen (broadened), I incline to look upon these differences as sexual, 

 though they do not uniformly correspond to the sex marks on the labels. 

 But in the Soricida, as in the Geomyidce, it is not safe to pin one's faith 

 too closely on the collector-s sexing. 



Measurements. — Type specimen: Total length, 126 mm.; tail verte- 

 brae, 57 mm.; hind foot, 14.5 mm. Average of 11 specimens from type 



