44 



U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



The cranium is too much mutilated to allow its shape to be determined, though the skull 

 generally appears to he much like that of B. talpoides. The dental formula is | -f g + 4 ~ = 32. 

 The anterior incisors are large and acute, placed quite close to each other. There is no internal 

 lobe, and there is no second hook at the base of the tooth distinct from the tip, as in some 

 American species. There is, however, a sharp lobe at the base, nearly rectangular, with a 

 slight angle in the anterior edge. The first two premolar teeth are much the largest ; they are 

 pyramidal acute, and like the basal lobe of the anterior, with a small process in the inner side. 

 The third and fourth lateral teeth are much smaller than the first and second, simply acute ; 

 the fourth nearly twice the third, and separated by a slight diastema from the first molar ; the 

 fifth tooth is very small, but visible from outside. The lower incisors are large, thick, and 

 much curved, with two lobes on the upper edge. All the teeth have their crowns and points of 

 a deep pitchy black, especially towards the latter. 



Measurements of 708. 



The specimen 2152, from the Little Blue creek, Nebraska, agrees very well with this speci 

 men, more so than with those from Fort Berthold and Iowa. The same may be said of the 

 number 2063 from Illinois. 



I have found very great difficulty in identifying with any certainty the Sorex brevicaudus of 

 Say, at least in the references to this species, as supposed to be found in the eastern portion of 

 the continent. I have, however, I think, discovered it in some specimens of very large size 

 from Nebraska and Iowa, localities nearer to that of the original specimen (Council Bluffs) than 

 of any specimens yet described. As most of Say's descriptions of vertebrata in Long's narra 

 tive were taken before the animals were skinned, the measurement from tip of nose to root of 

 tail of 3f inches, or 3.62, must be considered as indicative of a size greater than usual in the 

 S. talpoides (or dekayi), in which these dimensions are only once or twice noted in measurements 

 of about one hundred specimens. 



The shrews in question are not only larger in body than any seen from the eastern States, 

 but there is a very conspicuous superiority in the size of their skulls, a point of great import 

 ance in this group. The only specimen in alcohol is unfortunately too much mutilated to fur 

 nish a true length, but it is proportionally much larger than the largest fresh specimen I have 

 ever seen from the east, as will be seen by the comparative table of measurements. 



