DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 825 



the dorsal region, and on the yolk-sac, near the trunk. The cardiac pulsations were 

 vigorous and regular. The pectorals were distinct. Next day the movements of the 

 contained embryos were active, and some emerged at 5 p.m., most however issuing next 

 day (tenth after fertilisation, viz., 24th April) : they are delicate, translucent forms, 

 and swim vigorously near the surface. The pigment is characteristic (see p. 126). 



The oldest larva reared in the laboratory is shown in PL XVII. fig. 12. It is 

 distinguished by its black pigment-spots arranged in a double series along the edges 

 of the muscle-plates, the inner row in each case being somewhat fainter. Dorsally the 

 outer row reaches forward to the mid-brain. A dense pigment-band exists in the 

 subnotochordal region of the abdomen. Scattered spots of considerable size occur on the 

 mandible, over the cardiac region, and on the ventral surface of the abdomen. As in 

 many other forms the dark pigment abruptly ceases in front of the caudal region. The 

 yellow chromatophores are distributed generally over the head, trunk, and fin-mem- 

 branes. The eyes are bluish silvery, the snout is still blunt, and the mandible is stout 

 and prominent. The subepidermal serous space over the head is well marked, and 

 extends as far as the anal region. Three sensory organs are present in it. The otocysts 

 are comparatively large. The blood-corpuscles are distinct. This example nearly bridges 

 the gap to the post-larval forms. At this stage the great translucency of the species is 

 noteworthy, all the organs being most clearly observed. 



The earlier post-larval stages of the whiting, viz., those immediately following larvae 

 reared in the laboratory, are still somewhat obscure, though they probably closely approach 

 those of allied forms, such as the cod and haddock. The characteristic nature of the 

 larval pigment, however, would lead to the belief that in the brighter colours (e.g., yellow) 

 early differences may occur. Such, as a rule, were lost before they came under observa- 

 tion ; for all these delicate forms are dead and considerably altered before reaching the 

 deck, and the same remark applies still more decidedly to those immersed in spirit. The 

 pressure to which they are subjected in the large mid- water net, by the currents, and by 

 the weight of crowds of Appendicularians, Medusas, and Hydromedusse, as well as Cteno- 

 phores, would alone sufficiently explain this ; nor are these dangers obviated by the use 

 of large wide bottles at the extremity of the net. 



So far as present observations go, the young whiting appears to be recognisable as 

 such when from 9 to 12 mm. in length, examples of these stages occurring in August 

 (1886). The dorsal, anal, and caudal fins have permanent rays, and the several parts of 

 the two former are all outlined but not separated from each other. The pectorals form 

 large fan-shaped organs, but the ventrals are minute. Groups of black pigment- 

 corpuscles occur on the brain and along the sides of the dorsal and anal fins, while a line 

 runs in the median ventral region of the abdomen. The sides of the body posteriorly have 

 a more general sprinkling of black pigment than in the cod, which, however, it closely 

 approaches. No barbel is noticeable. 



When about 15 mm. long the species is distinguished by a more abundant covering 

 of minute black pigment-specks along the sides of the body and on the fins than in the 



VOL. XXXV. PAET III. (NO. 19). 6 N 



