lxii BREEDING. 



thousand eggs, which are agglutinated together in a mass, and subsiding 

 to the bottom, attach themselves 'to sea-weeds or other suitable substances ; 

 let this nidus for the eggs be trawled away or otherwise destroyed, and 

 the herrings may permanently, or at least for an indefinite number of years, 

 migrate to a more suitable spot. The sprat gives eggs of about 0*04 in. 

 in diameter, and these likewise sink to the bottom, but not in a mass or 

 covered with adhering substance, as in the herring. The shad of our 

 waters has not yet had this question investigated, but in the United States 

 the Fish Commission find that in the species which is most prized there, 

 Clupea sapidissima, the eggs sink, but that they require to be kept in 

 constant motion. Those eggs which normally float are more susceptible to 

 atmospheric changes, and possibly this may occasion much loss. Thus in 

 one genus are forms in which the eggs are agglutinated into a mass, sink, 

 and become attached to suitable fixed objects : in another they simply sink : 

 whereas in a third, although they sink, they require to be kept in constant 

 motion. 



If we take another family for investigation, as that of the salmon, trout, 

 and their allies, we find interesting variations. The common smelt, Osmerus 

 eperlanus, covers stones, planks, and suitable objects with its adherent 

 ova, and which are placed near the level of high water. These eggs 

 are furnished with fine filaments on their outer surface, which filaments 

 expand at their distal extremities into the form of a sucker for attach- 

 ment. The grayling deposits its ova about April or May, or even 

 earlier, on the gravel at the bottom of a suitable stream; they are not 

 placed in a nest and appear to be very delicate; their size is rather less 

 than seen in the trout. But the salmon, trout, and char fan up the gravel, 

 thus forming a trough wherein the ova are deposited, and subsequently 

 the nest, redd or rid, is covered over with the gravel, and here the eggs are 

 left to come to maturity. In all these forms the eggs are heavier than the 

 water in which they are deposited, still they are treated either by being laid 

 on the bed of the stream or below the gravel, but the fish culturist has 

 ascertained that this placing them within a bed or nest is not essential to 

 their hatching. 



Before passing on from the eggs and how deposited, I must draw atten- 

 tion to a rather curious phenomenon, but too often seen, and which in its 

 most fatal form is known as fish being egg-bound dying, in fact, unable 

 to void their ova, similarly to fowls unable to lay their eggs, or higher ver- 

 tebrates which cannot bring forth their young. Some fish, as the herrings, 

 which exude their ova in the open sea, can scarcely be subjected to any 

 extraneous force in order to assist this process, but that such does take 

 place in some fishes has been ascertained. The gold carp, Carassius 

 auratus, is one of these forms, and the male (or rather relays of them) have 



