MAMMALS SORICINAE SOREX THOMPSONI. 



35 



The upper parts are of a dark olive-brown, without any tinge of a reddish or chestnut, the 

 sides are a little paler. The under parts are of a dark ashy-white, likewise without any tinge 

 of rusty or yellowish. The difference in color between the back and belly is well marked. The 

 feet and under surface of the tail are brownish white. There is a slight hoariness on the back 

 produced by the lighter shade on the hairs near their points. 



Owing to its mutilation, the exact length and proportions of the entire skull cannot be ascer 

 tained. Dental formula -| -}- ^ -\- ^ = 30. The teeth are quite large ; the basal hook of 

 the anterior upper incisor about as large as the third lateral tooth, which is somewhat less 

 than the first and second, themselves equal. The third tooth touches the first molar and thus 

 conceals the small fourth tooth when viewed laterally. The lower anterior incisor has no lobes 

 or dentations in No. 247, while two of them are more or less distinctly indicated in Nos. 2062 

 and 1686. 



Measurements of No. 247, (dried skin,} probably stretched. 



This species is the smallest that has yet come under my examination, one specimen weighing 

 less than 22 grains. It is readily distinguishable by its olive-brown color and small number of 

 lateral incisors, as well as diminutive feet, from S. personatus and cooperi. In form it resembles 

 S. hoyi, but is much smaller in size and proportions, much darker in color, has larger ears, less 

 dentations on the lower anterior incisors, &c. It is barely possible that the two may be the 

 same, but of different ages and seasons ; but their differences are considerable, and both appear 

 perfectly adult in all points. 



As this species appears to be undescribed, I have named it after the late Professor Zadock 

 Thompson, of Vermont, one whose recent death has caused a gap in the ranks of local scientific 

 investigators, not soon to be filled. 



List of Specimens. 



