589 
COMMON MOLE; SHREW-MOLE. 
Scalopus aquaticus machrinus (Rafinesque). 
Talpa machrina Raf., Atlantic Journ., I., 1832, p. 61. 
The common mole, under various subspecific forms, is found 
over most of the eastern half of the United States. The range of 
the form called machrinus is given as Wisconsin and Minnesota to 
Tennessee and Missouri; and west to eastern Kansas, Nebraska, 
and southwestern South Dakota. 
Meern= imcisors; */5> canine, */,; premolars, °/,;, molars, */,. The 
second and third incisors of the upper jaw are small and often miss- 
ing. The molars and premolars have very irregular surfaces, the 
projections of the lower jaw fitting into corresponding hollows in 
the upper one, and vice versa. This construction of the teeth and 
the strictly up and down motion of the jaws are well adapted to the 
chopping up of insects or other animal food. 
The average size of twenty-seven adult specimens from Cham- 
*paten county is as follows: Total length, 7.13 m. (181 mm.); 
length of tail, 1.34 in. (34 mm.). Specimens from the western part 
of the state are someWhat larger. The fore limbs to the wrist, are 
concealed under the skin. The fore paws are enormously de- 
veloped. The toes, five in number, are webbed their whole length. 
The length of the palm is .6 to .8 of an. mech (15-20 mm.), but 
the width is greater, being from .8 of an inch to an inch (20-25 
mm.). This great width is due to a flap of skin on the lower edge, 
the rigidity of which is maintained by an extra sickle-shaped bone. 
The palm is margined with stiff hairs. The nails are stout, flattened, 
semi-cylindrical, and translucent enough to shew the bifid tips of 
the last finger-bones within. The tail is squarish, especially at the 
base. 
The nose is slender and pointed. The snout is prolonged be- 
yond the lower jaw about .3 of aninch (8 mm.). It is flattened and 
deeply grooved below, and is truncate at the apex. The truncated 
surface looks upwards and contains the nostrils. At the tip is a 
hard, nail-like body. The thick fur hides the eye and the ear, but 
if the hair be cut off close both may be found. The eye appears as a 
protuberance, about the size of a pinhead, .8 to 1 inch (20-25 mm.) 
from the end of the snout. There is no true pinna, or external ear, 
but the external auditory opening is prolonged a short distance 
beyond the head by a cartilaginous tube. 
