2 1 8 NEW GENUS AND SPECIES OF THE SORECID7E. 
relationships of Bendire’s Shrew, it must be compared with typical 
representatives of the genera to which it is most closely allied, and 
these are found to be Sorex and Neosorex — its affinities with 
Blarina being very remote. But, as preliminary to this inquiry, it 
becomes expedient to indicate the differences existing between the 
two first-mentioned genera. 
The only tangible diagnostic characters that have been assigned 
to the genus Neosorex are the long fimbriated feet, the great length 
of the tail, and the circumstance that the known species are “ sharply 
bicolor, blackish above and whitish beneath.” No distinctive 
cranial or dental characters having been pointed out,* I have in- 
stituted a comparison between the type specimen of Neosorex 
navigator f and a specimen of Sorex Coopcri. The differences 
noted are as follows : In Neosorex the rostrum is longer, and its 
sides meet the cranium at a decided angle ; while in Sorex the sides 
of the rostrum are but little out of line with the cranium. In 
Neosorex the rostrum is more sharply compressed just in front of 
the molariform series, so that its anterior portion is more attenuate, 
and the unicuspids more nearly parallel than in Sorex. The 
greater development of the facial portion of the skull is best 
shown in the lengthening of the upper jaw and the shortening of the 
lloor of the cranium. In Sorex, the ratio to the entire length of the 
skull of the distance from the front incisor to the hinder margin of 
the palate is 43.2 ; in Neosorex , 46.3. On the other hand, the ratio 
to the entire length of skull of the distance from the hinder margin 
o o 
*1 am aware that Coues, in his “Precursory Notes on American Insectivorous Mammals” 
(Bull. U. S. Geol. and Geog. Survey, Vol. Ill, No. 3, 1877, PP- 631—653), saysthat in Neosorex 
the posterior hook of the upper incisor is “as large as the succeeding tooth ” (p. 641). But Baird, 
in his original description of the genus, expressly states that the basal hook only equals the fourth 
unicuspid, which is considerably smaller than the first. Having the type specimen of N. navigator 
before me, and examining it with special reference to this point, 1 find that the basal hook is but 
little more than half— certainly not two-thirds — as large as the first unicuspid. 
f I am indebted to the courtesy of Professor S. F. Baird for the privilege of examining the type of 
Neosorex navigator (No. V35 0 )' together with several other representatives of the Neosorex group, 
belonging to the United States National Museum. My thanks are also due Captain Chas. E. 
Bendire and Dr. Elliott Coues for their kindness in selecting and transmitting the specimens. 
