GENERAL REMARKS ON THE EGGS OF MARINE FISHES. 15 



species throughout the ocean, tends to minimise the destruction 

 of the eggs by any special agency, and appears to have played 

 an important part in the preservation of the various food-fishes. 

 Little explanation of the first proposition is necessary, for it 

 can readily be understood how oceanic currents and tidal 

 changes carry the buoyant ova far and near, peopling regions 

 unknown to the adults and spreading such species as the cod 

 throughout the North Sea and both sides of the Atlantic, and 

 this altogether irrespective of the swimming powers of the 

 larval, post-larval, adolescent and adult fishes. In the case of 

 those fishes which inhabit the bottom and the range of which 

 in many cases is therefore restricted, the pelagic eggs and 

 young carry the species widely throughout the ocean — a 

 provision so conspicuously observed in fixed invertebrates, the 

 larval forms of which often have remarkable swimming powers. 

 The second proposition, that the pelagic eggs escape wholesale 

 destruction by special agencies, will be understood if the almost 

 invisible glassy spheres drifting in every direction are contrasted 

 with the masses of the ova of the herring deposited on the 

 bottom, and which form the food of hordes of haddocks, cod 

 and green cod (saithe) following in the wake of the spawning 

 fishes, the cod for instance greedily gulping the gravel to which 

 the eggs adhere in its eagerness to secure them. As many as 

 eighty boxes of large haddocks have been trawled^, every one of 

 which had its stomach distended with the eggs of the herring, 

 and this is but an indication of the enormous loss sustained 

 twice a year in the life-history of this species. A similar con- 

 trast may be made between the eggs of two rock-loving fishes, 

 viz. the lump-sucker and the rockling. The former deposits its 

 eggs in masses attached to ledges of rocks and stones, and they 

 are often laid bare by the tide, so that besides the depredations 

 of whelks and other forms in the water they are devoured by 

 crows, starlings, and in some cases even by rats when exposed 

 at ebb-tide, notwithstanding the faithful guardianship of the 

 male. The latter has pelagic eggs that are widely disseminated 

 through the water. 



It is true that occasionally pelagic eggs when occurring in 

 1 By Messrs Joseph Johnston and Sons, Montrose. 



