312 



EDWIN S. GOODRICH. 



It will be seen at once that tlie skeleton of this fin closely 

 resembles that of the pectoral fin of the same species already 

 described and figured by Whiteaves and Smith Woodward 

 (10 and 12) .1 In the pelvic fin (figs. 1 andF) we find an axis 

 consisting of three segments or mesomeres, and three pre- 

 axial endo-skeletal rays orparameres. Of these the first two 

 and largest are borne by the first and second mesomeres 

 respectively, whilst the last is in a rudimentary condition, 



Fig. a.— Ventral view of the pelvic girdle and fins of Heptanclius cine- 

 reus, Gm.; in this and the succeeding figures the complete skeleton is 

 exposed on one side only. For the lettering see the Explanation of 

 Plate 16. 



being represented by a small rounded piece at the distal end 

 of the outer branch of the slightly bifurcated terminal 

 mesomere. A similar semi-lunar piece fits on to the axial 

 branch of the third mesomere. The whole skeleton of the 

 fin is formed, then, of an axis consisting of three large 

 segments, and a small terminal piece, and of two well- 



' This resemblance was pointed out by Traquair {'i), who writes "A very 

 similar arrangement is found in the pelvic fin ... ; here J find at least two 

 mesomeres, each bearing a paramere, tliere being, I think, also a probability 

 of the presence of a third or distal mesomere." 



