242 



COMPARATIVE ANATOMY 

 I .3 2 ■' 3. 



ZS- - 



Pff- 



JiF-/r 



e 3 I 



c 



Fig. 193, A. — Tooth op Fkog, and 193, B, Salamandra atra. 



ZK, crown ; Z8, base ; EF, circular furrow ; <S', apex, covered with enamel ; 

 PH, pulp-cavity ; M, maxilla. 



Fig. 193, C. — Tb.4nsvebse Section through Portion of a Tooth of a Laby- 

 RINTHODONT (Mastodoiimuriis). (After J. Storrie. ) 



G.c, central pulp-cavity ; 1, inflections of the enamel, surrounded by dentine, 

 whicli reach the centre (c.e) ; 2, half-length inflections between 1 ; 3, short 

 inflections between 1 and 2. 



resembling the incisors of Mammals, and working together like 

 scissors; in some Fishes they give rise to a definite pavement, 

 are rounded in form, and serve to crush the food. They may. 



