LEPUS CUNICULUS 301 



small bony mass lying in between the tympanic and peri-otic bones 

 just in front of the stylomastoid foramen. It is hardly distinguish- 

 able in most dogs, though plain in some other mammals. The 

 remaining portions of the cornua passing from dorsal to ventral 

 end are the stylo-hyal, the epi-hyal and the cerato-hyal, which joins 

 the body near the thyro-hyal. 



A typical tooth consists of a crown, the portion standing out 

 from the gum ; a root, which is inserted in the jaw and may possess 

 one or more fangs ; and a slightly constricted region, the neck, joining 

 the other two. Within the tooth is a hollow, the pulp cavity, con- 

 taining the pulp, which is connective tissue richly supplied with 

 blood-vessels and a nerve. 



The main mass of the tooth is composed of the hard dentine. 

 The crown is capped with a still harder substance, the enamel, and 

 the . fangs are coated with cement. This is a softer substance 

 resembling bone, in that, it possesses lacunae and canaliculi, but it 

 has no Haversian canals. 



