236 NORTH STAFFORDSHIRE COAL FOSSILS. 



slender bone, filled with fine, sharp teeth. The premaxilla 

 and maxilla are small. The latter are in one piece and 

 both are filled with minute sharp teeth. The dorsal fin 

 commences at a point behind the dorsal ridge, and extends 

 to the commencement of the upper lobe of the tail. The 

 anal fin is of the same size and character as the dorsal. 

 Professor Young, in his description of this fish,* says 

 there is no evidence of the existence of a ventral fin. 

 Later discoveries, however, have demonstrated the presence 

 of this member ) 



Position and locality : Knowles ironstone, Fenton ; 

 Brown mine, Silverdale ; Apedale. 



Platysomus parvulus, var., J. Young, M.D. (Ref., Quart. 

 Jour. Geol. Soc., vol. xxii., p. 303.) This is a somewhat 

 larger fish than the last species. The chief difference 

 between this species and P. parvulus is the more oval 

 shape of the body and the absence of the angular dorsal 

 peak, so marked a feature in the above species. The scales 

 are similar in shape. The striae on the scales are finer 

 and the crests smooth. 



Position and locality : Knowles ironstone, Fenton and 

 Longton. 



FAMILY AMPHICENTRID^E, YOUNG. 

 GENUS AMPHICENTRUM, YOUNG. 



Amphicentrum granulosum, Young. (Ref, Quar. Jour. 

 Geol. Soc., vol. xxii., pi. xx.) The genus Amphicentrum 



* Quar. Jour. Geol. Soc., vol. xxii., p. 305. 



t Ann. and Mag. Nat. Hist., vol. for 1872, p. 253. 



