149 



embryo was about three-quarters the circumference of the egg, 

 and showed occasional movements. On the Sth it was 

 well developed. As a more advanced embryo had died at this 

 stage and this one seemed to be feeble, it was removed from 

 the egg, and the following characteristics observed (Plate IX, 

 fig. 52): there was little colouring matter, only a few black 

 branching cells being observed on head region and over yolk. 

 The rectum was median (somewhat nearer the yolk than the 

 end of the tail). The dorsal fin was low, and the tail came to a 

 point without any caudal expansion. The ventral fin was 

 deeper than the dorsal and the notochord was multicolumnar. 

 The most characteristic feature was a low triangular prominence 

 on the dorsal aspect over the centre of the yolk. 



On three occasions the eggs were procured alive, but the 

 larvae did not on any of these hatch out naturally. 



The eggs were procured as follows :— 



