THE HERRING FAMILY. 427 



4th day, the body has elongated and the supply of yolk is 

 rapidly diminishing, the eyes are now black and opaque, 

 whilst the black chromatophores have encroached upon the 

 ventro-lateral region : by the end of this day there is hardly a 

 trace of yolk. At the age of five days the larvae have reached a 

 length of 5'5 mm., and the yolk has entirely disappeared, bringing 

 to a close the true larval period. By ten days the whole brood 

 had expired, the conditions in captivity seemingly being un- 

 favourable to further development. We may notice in the nine 

 days' post-larval form the elongated body (cf. Herring and Sprat), 

 the long alimentary canal ending in a sub-terminal vent, and the 

 unicolumnar notochord. The continuous embryonic fin is still 

 present, being only interrupted by the vent. There appears to 

 be a very conspicuous post-anal gut, running from the vent to 

 the extreme posterior end of the notochord. A few fin-rays are 

 seen in the caudal region. The entire absence of all pigment 

 in the fins is noteworthy, as is also the presence of only black 

 pigment upon the trunk and head. 



From this brief account it may be said that we know the 

 leading features of the embryonic and larval development of 

 the pilchard, but we know nothing of the habitat in natural 

 conditions during this epoch. 



It is reasonable to suppose that the larva remains in the 

 surface and mid-water whilst the process of yolk-absorption is 

 proceeding, partly because of its helpless condition and partly 

 from the analogy of other forms, bat we must wait for further 

 light upon the fate of the post-larval forms. Do they move 

 downwards as they approach the shore and pass their young 

 stages at or near the bottom, as in the case of so many other 

 species, or do they remain at or near the surface ? These and 

 other questions must be left unanswered at present. 



In the work already referred to, Prof. Marion gives an 

 account of the sardine fishery and the names by which the 

 young pilchards are known at various stages in their growth. 

 He states that the young sardines remain for the whole of 

 the first year in the Gulf of Marseilles, and they grow at the 

 approximate average rate of 1 centimetre (= f in.) per month. 

 At a length of 2 to 4 centimetres they are known as ' poutines 



