346 JAMES ROLLIN SLONAKER 
examined only two of the Insectivora (Centetes and Erinaceus), 
but has not found this tuft of hairs in either of these forms. 
The tactile hairs on the manus of the mole may possibly corre- 
spond to this tuft, but, owing to the great modifications which 
have taken place in this animal, do not occupy the same relative 
position as in other mammals, as described by Beddard. 
According to Wood (’10), there is a small protuberance situ- 
ated between the eye and the ear in the mole which he thinks 
functions as an organ of touch. This evidently corresponds to 
the true vibrissae found in other mammals where they function as 
tactile organs. 
The innervation of the palmar surface of the feet is apparently 
not highly specialized, for Klaatsch (’88) claims that the moles 
show a very primitive condition in regard to the touch organs 
in the balls of the feet and hands. These organs function largely 
in the reflexes of balancing. Since the mole does not support 
any of its weight on its fore feet and only a little on its hind feet, 
this primitive condition would be expected. 
From this brief résumé one must conclude that the special 
sense on which the mole relies most is that of touch. This is 
just what one would expect when the habits and environment 
of the animals are considered. While the senses of smell and 
taste are of service in the selection of food, and the sense of hear- 
ing in giving a warning of approaching danger, touch is predomi- 
nant in bridging over the gap between the environment and the 
corodinated movements of the animal. On this sense it depends 
for its continued existence. The location of these special touch 
organs oh the snout and the edge of the manus is just where one 
would expect in the adaptation to its environment. The massing 
of Eimer’s organs at the tip of the snout, their gradual diminu- 
tion farther back, with tactile hairs becoming more numerous, 
again shows adaptation. The bare snout can be kept more free 
from dirt for fine discrimination than if it were covered with 
tactile hairs. The location of the tactile hairs on the edge of 
the manus is the best for guiding the movements of the fore legs 
in digging, in feeding, and in locomotion. Furthermore, the 
vibrissae on the cheek are reduced in length so that they do not 
