68 



On some Larval Stages of Fishes. 



By 



J. T. Ciiiiuingham, ]?I.A., 



Naturalist to the Association. 



With Plates III and IV. 



The six drawings reproduced in Plates III and IV were made at 

 sundry times from stages that I succeeded in obtaining in the years 



1889 and 1890. The three stages of the common sole were pro- 

 cured after my quarto book on that fish was completed, and they 

 enable me to supplement the account of the life-history of the species 

 given there. 



Fig. 1 represents a larva of Solea vulgaris four days after hatching. 

 The drawing reproduced was made from the living larva on April 26th, 



1890 ; the larva was hatched on April 26th from an egg artificially 

 fertilized on April 14th on board a trawler off the north coast of 

 Cornwall. The temperature of the surface water of the sea in 

 which the eggs were fertilized was 9-7° C, of the water in the 

 Laboratory in which the eggs were kept 10"8° C. The variations 

 of temperature in which the eggs were carried while on board the 

 trawling smack were not observed. I can only, therefore, give an 

 approximation to the relation between temperature and the period 

 of development of the egg, namely, that at a mean temperature of 

 about 10'0° C. the eggs of the sole hatch in eight days. 



The condition of the larva of the sole immediately after hatching 

 is described and illustrated in my Treatise on the species. The 

 changes which have occurred in the stage represented in fig. 1 are the 

 following : The yolk, yh, is much reduced in bulk, about half the 

 quantity present at hatching having been absorbed. Three groups 

 of oil globules are still visible on the surface of the yolk, the 

 individual globules being larger than in the newly hatched larva, 

 doubtless because some coalescence has occurred. In the newly- 



