CHANGES FOR ADAPTATION IN THE MOLE 361 
symphysis, and, c. with no pubic symphysis. Under this last 
group he placed the Talpidae and considered it the most primi- 
tive group. 
Many authors, when stating that there is no pubic symphysis 
in the mole, have under consideration the species Talpa europaea. 
But the general statement so often found that a pubic symphysis 
does not exist in the Talpidae will have to be modified. 
Another modification is seen in the dorsal spines of the sacrum. 
These have coalesced to form a median dorsal crest 20 mm. 
long and from 2 to 3 mm. high extending almost the entire length 
of the sacrum. This crest and the long bridges between the 
sacrum and the pelvic bones provide sufficient strength to com- 
pensate for the weak or complete absence of the pubic symphysis. 
The hind legs of the mole are more frail than is usual in a mam- 
mal of this size. In the femur, the tibia and fibula (pl. 4) there 
is no great modification in the form of these bones. The tibia 
and fibula are united for more than half their length from the 
distal end. The proximal ends of each of these bones have a 
decided hook-like process on the lateral side, which extends. 
outward and downward, approaching each other somewhat 
toward their tips. The foot is plantigrade. It is relatively 
long and slender, measuring from 22 to 25 mm. from heel to 
tip of claws. The claws are slender. The whole foot suggests. 
weakness. 
Owing to the great reduction in the pelvic outlet, a most 
remarkable change has occurred in the relation of the urogenital 
and alimentary tracts to the pelvic arch. The outlet is so small 
that it is impossible for these tracts to pass through the arch 
as in most mammals and still function. The result is that they 
are wholly excluded and lie ventral to the pubic symphysis. 
That this relationship in the mole was known to naturalists 
long ago is evidenced by the following quotation from Wood’s 
(59) article on the pelvis in Todd’s Cyclopedia of Anatomy and 
Physiology. He says: 
The Mole (Talpa) and the Shrews (Sorex) etc. are remarkable for a 
very narrow sacrum, composed, according to Blainville, of four verte- 
brae, but, according to Cuvier, of seven in the Mole and three in the 
