538 CHORDATA. 
mole being no exception. The incisors are small and 
chisel-shaped, the canines somewhat prominent in the 
upper jaw, but more like incisors in the lower, in which 
the first premolar resembles a canine. The premolars 
as a whole are simple and conical, and the molars are 
tuberculate, having sharp conical cusps adapted for tearing 
and crushing rather than grinding. These teeth are pre- 
ceded by a complete milk-dentition. 
The vertebral column is a strong axis, and the constituent 
vertebree are articulated together by very “strong surfaces.” 
The dorso-lumbar vertebrz are usually nineteen, a common 
mammalian number. The pelvis is attached to six vertebree. 
Fig. 371.—JAWS OF TEETH OF THE MOLE x 3. 
Note the tubercular molars and the incisor-like lower canine followed by 
acaniniform premolar. Dental formula $}43. 
Between the dorso-lumbar vertebrae are small extra bones, 
sometimes called ‘“intercentra,” represented in most mam- 
mals by mere discs of cartilage (intervertebral discs). The 
ribs are well formed and taper off rapidly forwards. At the 
front end of the sternum there is a large and conspicuous 
“ presternum,” which in great part appears to represent the 
episternum as found in AZonotremata. The first pair of ribs 
are strong and short and support the base of the episternum. 
At the front end just under the throat the episternum forks, 
and to it is attached on each side a short strong cylinder of 
bone. This bone is usually termed the clavicle, but as it is 
ossified partly from membrane (clavicle) and partly from 
