Article I. — On the Common Shreiv-mole, Scalopiis aquaticiis 

 machrinus (Rafincsqitc), in Illinois. By Frank Eemer Wood.* 



There are two species of moles in Illinois : one, the starnose mole, 

 Condylura crisfafa (LinncCus), is found sparingly in the northern 

 part of the state ; the other, known as the common or shrew-mole, 

 Scalopus aquaticiis (Linn?eus), is the one with which this paper deals. 

 It is distributed throughout most of the state, and apparently all our 

 specimens may be referred to the western subspecies machriniis (Raf- 

 inesque). 



The general range of the species, under various forms, extends 

 over most of the eastern half of the United States. Its northern 

 boundaiy is a line running from the southern point of Maine west- 

 ward through New Hampshire, Vermont, New York, Ontario, and 

 Michigan, and thence northwestward to a point on the Red River of 

 the North near the Canadian boundary. Its western limit is near a 

 line from that point to the mouth of the Rio Grande. The mole is 

 found also for a short distance along the Gulf of Mexico, but not in 

 southern Florida. Over this range there is considerable variation in 

 size, color, and some other characters. In general, specimens from 

 the arid regions of the West are lighter in color than those from 

 sections in the east and south which have a moister climate. The 

 smallest variety is found in Florida, and, judging from data at hand, 

 specimens from Illinois attain the largest average size. In the At- 

 lantic States northern specimens average larg'er than southern ones, 

 and it is true in general for all states east of the Mississippi that 

 eastern specimens are smaller than western ones from the same lati- 

 tude. There appears to be considerable variation in size even within 

 the state as is shown by the following tables. 



True gives the average lengih of six specimens from Illinois as 

 follows: total length, 188.7; head and body, 154-9; 3-"^ tail, 33.8. 

 Apparently these specimens were all from the western border of the 

 state. This would indicate a gradual increase in size from east to 

 west across the state, and that the maximum size was reached near 

 or beyond the Mississippi River. 



*Some matter on the mole, additional to that used in the present article, 

 may be found in "A Study of the Mammals of Champaign County. Illinois," 

 by F. E. Wood, published in May, 1910, as article 5 of Volume VIII of the 

 Bulletin of this Laboratory. 



