FOSSIL AND RECENT 



137 



r p 1-4 



cor 



5mm 



Fig. 67. Pterothrissus gissu Hilgendorf. Pectoral girdle of right side in medial view. 



entirely by cartilage. In shape and disposition this radial resembles members of 

 the cartilaginous distal radial series. This partially ossified distal radial, together 

 with the base of the outermost fin-ray, fits into the depression upon the scapula. 



Of the 16 pectoral fin-rays only the first is unbranched. Little may be said of the 

 length of the rays since the tips of the fin-rays were missing in all specimens examined. 

 To judge by the width, the second is the longest pectoral ray. A small pectoral 

 splint bone is associated with the base of the outermost ray. The proximal end of 

 the splint is turned slightly upwards and markedly inwards to contact the small 

 distal radial mentioned above. It is therefore unlike the pelvic splint bone in which 

 the proximal end lies free in the body musculature. 



