.EGGS AND NESTS. Ixi 



Among the curious pipe-fishes the eggs are transferred from the female 

 to the male, and in most of the species the duty of hatching them devolves 

 on the latter sex, for which purpose they are deposited up to the period 

 of the evolution of the young in ovigerous sacs variously placed (vol. ii, 

 page 256). In the horse-fishes {Hippocampus) in pouches under the tail j 

 in our ocean pipe-fishes {Nerophis) in rows along the breast and Ijelly. 

 Whether this phenomenon of carrying about the, eggs is to protect them 

 from danger or iti order to change the water in whi'ch they are kept may be 

 questionable, but as these fishes have several times been hatched in aquaria, 

 it would seem to be for the, purpose of protection against foes. Similarly 

 we perceive siluroids, Arilnw, of' the Eastern and other seas in which 

 the males carry -about the ova in their mouths, either continuously or 

 temporarily, and the young may be observed emerging from the oyum while 

 it is still in the maw of the male fish. Teleosteans, which have no oviduct, 

 as the Salmoiiidce, deposit their eggs detached, one from the other; but 

 such as possess oviducts often have them surrounded by a viscid secretion, 

 formed from the lining membrane of the oviduct and agglutinating them 

 in lumps or cords. 



The sticklebacks or- pricklebacks of this country (vol. i, page 236), 

 whether marine or fresh-water species, form a nest for the reception of their 

 eggs, which has an entrance on one- side and an exit on the other, so that 

 either parent can readily pass through. When the eggs have been safely 

 deposited in the nest, and the necessary fertilization accomplished, the male 

 takes charge, driving his h.elp-mate off to a safe distance in order to prevent 

 her making a meal of the ova. Mr. Warrington ascertained that in a few 

 days in the fresh-; water species the nest was more and more opened by 

 the. male, evidently owing to- the necessity for oxygenation, and he hovered 

 over it, causing a current of water to be propelled across its surface by 

 fanning it with his fins, and after about ten days the nest was destroyed 

 and minute fry appearedj over which the male kept guard. Some of our 

 marine wrasses of the genus Grenilahrus have been observed to construct 

 nests, in which occupation both sexes assist. The river bullhead, Gottus 

 gohio, forms a hole in the gravel at the bottom of a stream, and here it 

 keeps guard over its eggs as well as over the infant progeny. While in 

 tropical countries there exist many forms of nest-constructing fishes, and 

 the parents,, more especially the male', protect the young until old enough 

 to shift for themselves. 



In investigating single families' of fish, or genera, it is interesting to 

 see how even closely related forms differ -in the places where they deposit 

 their ova, or the period when they breed. Among the herrings we find 

 that the common herring is breeding in some one or other spot around our 

 coast almost every month in the year ; that it deposits from ten to thirty 



