154 



TELEOSTOMES 



Diplurus has become excessively shortened in its body 

 length ; the head is of relatively enormous size ; its derm 

 bones are squamous, and appear to have been deeply 

 implanted in the integument ; teeth have disappeared ; 



Fig. 156. Diplurus longicaudatus , Newb. X \. Triassic, Boonton, NJ. 



A. Position of calcified swim-bladder. A" '. Second anal fin (now the ventral 

 portion of the functional caudal) . BR. Radial and basal fin supports. C. Caudal 

 fin (degenerate). D, Hindmost dorsal fin (now the dorsal portion of the func- 

 tional caudal). J. Jugular. 



scales have become exceedingly thin and are rarely pre- 

 served. Fin structures are apparently of a degenerate 

 character ; their cartilaginous bases, when showing, appear 



Fig. r$6 A. Undina gulo, Egert. 

 (Restoration after SMITH WOODWARD.) 



Lower Lias of Lyme Regis. 



to have become reduced to single plates, as BR ; the 

 caudal is the elongate tip, of the vertebral axis ; the 

 functional caudal, now elongate and diphycercal, is formed 



