THE SKELETON OF THE DOGFISH. PELVIC GIRDLE. 81 



long narrow 



The meta-pterygium bears about twelve 

 radials, the first nine of which are traversed by a transverse 

 joint at about two- thirds of the way from their origin. Suc- 

 ceeding the radials are a series of small polygonal pieces of 

 cartilage arranged in one or more rows and attached to the ends 

 of the radials, and finally the fin is completed by the dermal 

 fin-rays. 



FIG. 8. DORSAL VIEW OF THE PELVIC GIEDLE AND FINS OF A 

 MALE DOGFISH (Scy Ilium canicula). 



1. pelvic girdle. 



2. basi-pterygium. 



3. clasper. 



4. radialia. 



THE PELVIC GIRDLE is much smaller than the pectoral. 

 It is formed of a stout nearly straight bar of cartilage placed 

 transversely across the ventral region of the body. The bar 

 has no dorsal or lateral extensions, and is terminated by short 

 blunt processes. It bears on its posterior surface a pair of 

 facets with which the pelvic fins articulate. 



THE PELVIC FIN is smaller and more simply constructed 

 than is the pectoral. It consists of a long, somewhat curved 

 R. 6 



