Tlate XVII. 



Fig. 1. Larva of Thickback newly hatched, April 24, 1889; magnilied 35 times. 

 Pigment as seen by reflected light, yk. yolk. 



Fig. 2, Larva of same two days after hatching, April 23, 1889. Same magnification 

 2^. pectoral fin. Jd. heart. 



Fig. 3. Larva of Flounder {Pleibronectes flesus), two days after hatching, February 20, 

 1889, from egg artificially fertihsed ; magnified 35 times. 



Fig. 4. Larva of same six days after hatching, February 24, 1889, from the same 

 lot as the preceding ; same magnification. 



Fig. 5. Young Flounder taken in Mevagissey Harbour, April 2, 1889 ; drawn K])v\\ 5 ; 

 nuignified about IS times. 



