PLATE XVII. 



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

 Pigment as seen by reflected light, yk. yolk. 



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

 pt. pectoral fin. ht. heart. 



Fig. 3. Larva of Flounder (Pleuronectes Jlesus), two days after hatching, February 20, 

 1889, from egg artificially fertilised ; 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 April 5 ; 

 magnified about 18 times. 



