THE LIFE-HISTORY OF THE SALMON. 297 



of pelagic eggs, its mouth is open at its birth, and its store of 

 yolk is sufficient to nourish it for five or six weeks ; whereas 

 the young hatched from a pelagic egg, as a rule, is devoid of a 

 mouth, has a small quantity of yolk, which in the Cod lasts 

 only nine days, and is a minute transparent speck scarcely 

 visible in the water except for the shimmer it makes when 

 moving. It has at first no definite circulation, whereas the 

 young Salmon has on its first day a most complex and complete 

 series of arteries and veins. 



The Wolf-Fish, amongst marine fishes perhaps, most nearly 

 approaches the Salmon in the demersal condition of its eggs 

 and in their comparatively large size, but it differs in having 

 oviducts to convey the eggs to the exterior, and in the fact that 

 the eggs are firmly agglutinated into a mass, and contain a 

 single large oil-globule. The fishes on hatching are readily 

 distinguished thus : — 



Wolf-Fish. Salmon. 



1. Yolk, and contained oil-globule Yolk of reddish orange colour, 

 of inconspicuous colour, and and elongated in outline, 

 yolk-sac spheroidal. 



2. Single large oil-globule, an- Many small oil-globules in upper 

 terior in position. part of yolk-sac. 



3. Snout blunt, so that eyes at the Snout protrudes well in front of 

 most anterior part of head. eyes. 



4. Marginal fin continuous. Marginal fin forming separate 



median fins. 



Neither the Wolf-Fish nor the Salmon pays the slightest 

 attention to its eggs after deposition, and thus they form a con- 

 trast with the next species, viz. the Lump-Sucker (155,000 eggs). 

 In this form the eggs in the ovaries agree with those of the 

 two former fishes in ripening nearly simultaneously, and they 

 form large amethystine masses attached to the rocks between 

 tide-marks; but, instead of being forsaken after deposition, they 

 are jealously guarded by the male, a smaller and more brightly- 

 coloured fish than the female. So faithfully does the male dis- 

 charge this duty that at extreme low water it may happen that 

 most of his body is exposed, so that carrion crows destroy the 

 eyes and even puncture the abdomen for the liver of the reso- 

 lute guardian. 



The Gunnel is about as careful of its eggs as the foregoing, 



Zool. 4th ser. vol. XVIII., August, 1914. 2 A 



