MAKINE BIOLOGICAL STATION AT PORT ERIN. 101 



April 17th, we trawled mature fish of various kinds both 

 flat and round, but did not succeed in getting both males 

 and females of the same species in the ripe condition, and 

 consequently no eggs were fertilized. On Monday, April 

 19th, we were more fortunate, and obtained to the north- 

 west of Port Erin Lemon Soles and "Witches" spawn- 

 ing, and were able to fertilize the eggs. We also found 

 spawning Megrims (Arnoglossus later na), and, as an 

 experiment, we fertilized the eggs with the milt of a ripe 

 Cod. As a result large numbers of the following embryos 

 were started on their development in the Aquarium on the 

 afternoon of the 19th : — 



In tank I. — Lemon Soles (Pleuronectes microcephalics) . 



In tank II. — " Witches " (Pleuronectes cynoglossus) . 



In tank III. — Ova of Megrim fertilized by milt of Cod. 



The arrangement of the hatching tanks, and the 

 apparatus for the circulation of the water was described 

 and illustrated in last year's Report.* The water during 

 the hatching kept at a specific gravity of from "26 to "27 

 and at a temperature of from 46° to 47° Fahr. The cross 

 between the Megrim (a flat fish) and the Cod only 

 developed for from three to four days, and then all the 

 embryos became abnormal and distorted, and died. 



On April 26th the Witches began to move inside the 

 egg covering, on the 27th the Lemon Soles were wriggling, 

 and on the 28th both hatched out, eight and a half days 

 after fertilisation of the eggs. 



We have now shown conclusively that sea-fish hatching 

 can be carried on readily at Port Erin, and beyond this 

 experimental stage, dealing with only a few hundreds of 

 eggs at a time, we cannot with our present accommodation 

 and appliances pretend to go. If hatching on an industrial 



* See Trans. Biol. Soc, vol XI., p. 67 and Pis. I— IV 



