80 



THE VERTEBRATE SKELETON. 



while the most posterior one, the meta-pterygium. (fig. 7, 3), 

 is much the largest. Along the outer borders of the three 



FIG. 7. SEMIDORSAL VIEW OF THE PECTORAL, GIRDLE AND FINS 



OF A DOGFISH (Scyllium canicula) x f . 

 The gaps between the radialia are blackened. 



1. hollow in the midveiitral part 5. 



of the pectoral girdle which 6. 



supports the pericardium. 7. 



2. dorsal (scapular portion) of 8. 



pectoral girdle. 9. 



3. meta-pterygiuin. 



4. meso-pterygium. 



pro-pterygium. 

 pro-pterygial radial, 

 meso-pterygial radial, 

 meta-pterygial radial, 

 outline of the distal part of 



the fin which is supported 



by horny fin-rays. 



basalia are arranged a series of close set cartilaginous pieces, 

 the radialia. The pro-pterygium supports only a single radial, 

 which is however much larger than any of the others. The 

 meso-pterygium also supports only a single radial which divides 

 distally. 



