CHANGES FOR ADAPTATION IN THE MOLE 343 
weather and moisture. Grubs, beetles, and some vegetable 
matter made up the balance. He considers the vegetable matter 
accidental and concludes that the damage to vegetation which 
the mole may produce is due to its method of digging and to 
mice which occupy the burrows later on. 
West (10) examined the stomach contents of thirty-four moles 
collected from various sources and found earthworms consti- 
tuted 31 per cent; adult insects, 23 per cent; insect larva, 29 
per cent; vegetable matter, 13 per cent. He concludes that the 
mole is beneficial and the vegetable matter was eaten acciden- 
tally. 
From the examination of thirty-six stomachs Wilson (’98) con- 
cludes that the mole does not intentionally take vegetable matter 
as food. He considers the mole beneficial, though it may acci- 
dentally do some harm. He says that the great damage to 
vegetation is due largely to the mouse family, Arvicolinae, which 
take possession of the runways. 
According to Ritzema (’98), the mole stores up food for use 
during the cold weather. He mentions finding 300 earthworms, 
each of which was decapitated, in a single nest in the winter. 
He also mentions the finding by Stadt of a ball of earthworms in 
a nest in winter. Each of the worms had from three to five of 
the anterior segments bitten off which led him to conclude that 
this was intentional. The cold weather delayed regeneration 
and the loss of the anterior segments prevented eseape. In 
this way the mole was assured a supply of food sufficient to tide 
it over periods unfavorable for securing food in the runways. 
The mole is a fossorial animal spending practically the whole 
of its life under the ground. It is occasionally seen on the 
surface at rare intervals and but for a brief time. In order to 
adapt it to its peculiar subterranean life, a number of structural 
changes have taken place. 
Even though no external aural appendage is present (Huxley, 
90; Herrick, ’92), the sense of hearing is apparently rather 
acute. I have found that the auricle in Scalopsaquaticus is repre- 
sented by a ring of cartilage surrounding the auditory meatus. 
This forms a ring-like expansion of the skin which rises slightly 
