350 JAMES ROLLIN SLONAKER 
foramen.’ Parascalops: ‘“‘clavicle relatively longer and weaker 
than in Sealopus and Seapanus, length about equal to breadth, 
penetrated anterio-posteriorly by a foramen near the inferior 
border.”’ Condylura: ‘‘Clavicle relatively long and narrow 
(for Talpidae), length about twice the breadth, sightly concave 
superiorly and convex inferiorly, not penetrated by a foramen.”’ 
Neiirotrichus: ‘‘ Clavicle relatively long and narrow (for Talpidae), 
length about twice the breadth; concave superiorly, inferior sur- 
face with a flat process projecting posterio-laterally; not pene- 
trated by a foramen.” The clavicle thus varies from a short 
stout bone two-thirds as wide as long to a relatively long bone 
one-half as wide as long. This modification accords fairly closely 
with similar changes in the manus to be described later. 
The proximal end of the clavicle consists of a vertical groove 
6 mm. long by 1.5 mm. broad which fits closely to the elongated 
convex surface of the T-like process of the presternum. This 
constitutes a simple hinge-joint and allows a slight movement in 
a forward and backward direction. Parsons (’01) claims that 
in the giant golden mole (Chrysochloris trevelyani) there is no 
synovial cavity between the presternum and the clavicle, but 
that the joint is nevertheless very flexible. 
According to Parker and Haswell (’10), the clavicle in the mole 
represents a precoracoid as well as a clavicle. They base this 
statement on the method of development, claiming that the 
posterior part is developed from a mass of cartilage, while the 
anterior part, which early becomes attached to the cartilage 
mass and which represents the clavicle, is formed, as usual, in 
membrane. 
The humerus of the mole would scarcely be recognized as 
such if isolated from its connections (figs. 1, 2, 3 8, 9, 10). 
These figures show that it is extremely irregular and that it has 
been very greatly changed from the humerus of typical mammals. 
The broad, thick, and short mass of bone gives great strength, 
while the great irregularity increases the surface for the attach- 
ment of the powerful muscles used in digging. It is 15 mm. long, 
11.9 mm. broad, and 5.4 mm. thick. The large indentation on 
the anterior edge, partly inclosed by the epicondylus lateralis 
