2 26 THE VISCERA. 



jaw is small and lies caudomediad of the last premolar. It has 

 two small cusps and two fangs. 



Fig. 94. — Mandible, with Roots of the Teeth Laid Bare. 

 a, incisors; b, canine; c, first premolar; d, second premolar; /, molar. 



In the lower jaw (Fig-. 94) the two premolars {c and d) are 

 similar, the caudal one being a little larger. Each has four 

 cusps; a single large one, a small one craniad of this, and two 

 small ones caudad of it. Each has two fangs. The single 

 molar (/) is the largest tooth of the lower jaw ; it has two large 

 cusps and two fangs. 



The Deciduous Teeth. — At birth the cat has no teeth. 

 There appears later a set of twenty-six teeth : twelve incisors, 

 four canines, and ten molars (six in the upper jaw and four in 

 the lower). These teeth are later replaced by the permanent 

 ones above described. The deciduous teeth of the cat are fully 

 described by Jayne ("Mammalian Anatomy," vol. I. p. 319), 

 where also an account is given of the order of appearance of 

 the teeth. 



The Tongue. Lingua (Fig. 95). — The tongue is a 

 muscular organ covered with mucous membrane ; in life it is 

 very mobile. It is an elongated organ, flat above, broadest in 

 the middle, and very slightly narrowed at each end. It 

 extends from the incisor teeth to the isthmus faucium and 

 nearly fills the mouth cavity. The caudal third of the tongue 

 forms the floor of the mouth cavity, so that the tongue has here 

 no ventral surface, but is directly continuous with underlying 

 organs. It is in this region that the extrinsic muscles of the 

 tongue (except the genioglossus) enter it. The cranial two- 

 thirds of the tongue is partly or entirely free from the floor of 

 the mouth, the cranial one-third being completely free and 

 movable. In about the middle third the ventral surface of the 



