632 
INSECTIVORA 
the young—generally from four to six in number—which are 
sy 
any 
\ 
Fic. 290.—Skeleton of Mole x 2 (ower jaw 
removed to show base of skull). c, Caleaneum; 
¢.h., clavicular articulation of the humerus; cl., 
clavicle; e.c, external condyle of humerus; f, 
femur; fb, fibula; fc, falciform bone (radial sesa- 
moid); h, humerus; i.c, internal condyle of 
humerus ; i, left ilium; ip, ramus of the ilium 
and pubis; is., ischium; l.d, ridge of insertion of 
Jatissimus dorsi muscle ; J.t, lesser trochanter ; m, 
manubrium sterni; 0, fourth intercentral ossicle ; 
ol, olecranon; p., pubis widely separated from that 
of the opposite side; pa., patella; p.m., ridge for 
insertion of pectoralis major muscle; pt., pectineal 
eminence; r, radius; rb, first rib; s, plantar sesa- 
moid ossicle corresponding to the radial sesamoid 
(os faleiforme) in the manus; se., scapula; Sh, 
scapular articulation of the humerus; t, tibia; u, 
ulna. 
brought forth in about six 
weeks, quickly attain their 
full size. 
The Mole exhibits in the 
whole of its organisation a 
perfect adaptation to its 
peculiar mode of life. In 
the structure of the skeleton 
(Fig. 290) very striking de- 
partures from the typical 
mammalian form are notice- 
able. Thus the presternum 
is so much produced anteriorly 
as to extend forward as far as 
a vertical line from the second 
cervical vertebra, carrying 
with it the very short and 
almost quadrate clavicle, which 
is articulated with its anterior 
extremity and distally with 
the humerus ; being also con- 
nected ligamentously with the 
scapula. The fore limbs are 
thus brought opposite the 
sides of the neck, and from 
this position a threefold ad- 
vantage is derived: in the 
first place, as this is the 
narrowest part of the body, 
they add but little to the 
general width, which, if in- 
creased, would lessen the 
power of movement in a 
confined space ; secondly, this 
position allows of a longer 
fore limb than would other- 
wise be possible, and so in- 
creases its power ; and, thirdly, 
although the entire limb is 
relatively very short, its an- 
terior position enables the 
animal, when burrowing, to 
thrust the claws so far for- 
ward as to be in a line with the 
end of the muzzle, the import- 
