538 



CHORD AT A. 



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 

 vertebrae are articulated together by very " strong surfaces." 

 The dorso-lumbar vertebrae are usually nineteen, a common 

 mammalian number. The pelvis is attached to six vertebrae. 



Fig. 371.— Jaws of Teeth of the Mole x 3. 



Note the tubercular molars and the incisor-like lower canine followed by 

 a caniniform premolar. Dental formula f ff f . 



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 Monoire^nata. 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 



