]35 



eleven, the rest were not found till afterwards when the decks were cleared np. Of 

 these eleven, three were females almost spent but still containing some ripe ova : one 

 was a female still unripe, four were spent females, and three were males. I got 300 

 or 400 ecro-s altogether which I tried to fertilise as before by crushing testes in the 



GO O O 



water. At 4.30 p.m. the same day from six soles taken I got about a dozen more ova. 

 On April 12, at 8 a.m., after a good night's haul, fifty-seven soles were brought on 

 deck. Of these fifteen were small, under nine inches in length, and not sexually 

 mature ; eighteen were males ; nineteen large females entirely spent ; five large females, 

 which yielded a few ripe ova. 



I may conveniently refer to the eggs obtained from the different hauls of this cruise 

 as lot ], lot 2, and lot 3. On April 12, while still at sea, I observed that a large 

 proportion of the eggs of lot 1, fertilised the previous day, had died and sunk. These 

 were probably not fertilised, but I do not know why the . fertilisation had failed ; it 

 may have been because the males were either immature or spent. I found when I 

 returned to the Laboratory, on April 13, that only eight eggs in lot 1 were alive and 

 developing ; in lot 2 some were floating but none fertilised ; in lot 3 two or three ova 

 were alive and developing. 



On April 15, there were altogether nine eggs left alive : of these I preserved two 

 for microscopic examination and left the other seven in a small glass jar provided 

 with a circulation, not in one of the hatching jars above described, but an ordinary 

 jar, the only difference in the arrangement being that the overflow of the water took 

 place through a protected siphon, the jar standing in the air, not in the water of a 

 tank. On April 16, I again went to sea, and returned on April 20, when I found 

 of the seven eggs I left in the Laboratory two were hatched, two alive but unhatched, 

 and the rest dead. The circulation had almost stopped, the supply tube having got 

 choked. On April 21 the two larvae were dead, and one of the eggs: the last egg 

 hatched on April 22, but died the same day. 



The above results prove that it is possible to artificially fertilise the eggs of the 

 sole and to hatch the eggs so fertilised in a hatching jar provided with a circulation. 

 They prove also that the cause of the death of the large number of eggs brought from 

 Penzance was not in any of the conditions to which they were exposed in the 

 Laboratory. The reason that I did not place the seven eggs just mentioned in a large 

 hatching jar was that it is difficult to find such a small number in such a jar, or 

 extract them for closer examination. 



POSTSCRIPT (May 3, 1890). While these pages have been passing through the 

 press the spawning period of the sole has again arrived, and I have renewed my 

 endeavours to perfect a method of artificial propagation. In consequence of 

 previous experience my success has been greater than in former seasons. During 

 a week I spent on a Lowestoft trawler in the Bristol Channel from April 9 to 

 April 16, I obtained a large number hundreds of thousands of ripe soles' 



