APPENDICULAR SKELETON. 231 



extends along the inner or attached border of the 

 fin, and corresponds to the basi-pterygium of the 

 pelvic fin, is much the largest. 



From the outer borders of the basal cartilages 

 a series of close-set radial cartilages diverge : of 

 these the pro-pterygium supports a single large 

 one; the meso-pterygium also supports one, 



Fia. 48. — Scyllium canicula. The pectoral girdle and fins of a male 

 seen from the ventral surface. In the right fin the cartilaginous 

 skeleton is shown, in the left the muscles and horny dermal fibres. 

 (a. m. m.) 



A, pro-pterygium. AF, pro-pterygial radial. B, meso-pterygium. BF, 

 meso-pterygial radial. C, meta-pterygium. CF, meta-pterygial radial. E, 

 polygonal cartilagiuous plates. H, homy fibres. M, muscles of fin. P<3-, 

 ventral portion of pectoral girdle. PG', dorsal portion of pectoral girdle. 



which is, hov?ever, split distally into two or 

 three ; while the meta-pterygium supports twelve 

 or more much narrower radials. 



To the outer ends of the radials two or more 

 rows of polygonal plates of cartilage are attached, 

 forming the peripheral portion of the skeleton. 



Horny fibres are present in large numbers, 

 as in the pelvic fins. 



