PELVIC GIRDLE AND FIN OF EUSTHKNOPrEllON. 315 



we find in the Clioudrostei somewhat ill-defined, more or 

 less tinangular, cartilaginous plates stretching from the 

 base o£ the pelvic fins towards the middle line (Fig. C). 

 Aniia lepidosteus and all the "Teleostei," in fact nil 



Fig. I). — Ventral view of tlie pelvic girdle and fin of a female Pleura- 

 eantlius Oelbergensis, Fr. (from Fritsch). 



the Actiuopterygii, possess paired bony ventral plates sup- 

 porting tlie pelvic fins. These plates may be joined together 

 in front by a median cartilage, as in Gradus (Fig, J), or they 



Fig. E. — Ventral view of the pelvic girdle of Pleuracanthus Gandryi, 



Brogn. 



may be merely united b}^ ligament (Figs. H, I). In the 

 Dipnoi, on the contraiy, the pelvic support is i*epresented by 

 a median cartilage with two diverging branches, to which are 

 articulated the fins (Fig. K) . Of the so-called Crossopterygii, 



