252 THE BIOLOGY OF THE SEA-SHORE 



moment in the fortnight at which the sex cells will be set 

 free. 



Care o£ Eggs by Parents. — The eggs of shore species 

 are not always deposited at haphazard, but are frequently, 

 after extrusion, the object of special attention on the part of 

 the parents. This phenomenon, though not confined to 

 the shore, is yet very characteristic of it. Obviously, the 

 danger from which the eggs are protected by this habit 

 lies in the attacks of predaceous animals rather than in 

 physical factors. As regards the latter, as we have seen, 

 the method of telescoping the life - history is more 

 likely to secure survival. In most of the familiar species 

 of Crustacea, the eggs, until the time of hatching, remain 

 attached to the female after extrusion, either stored in sacs 

 at the side of the body (Copepods), or attached by a 

 sticky secretion to the numerous hairs on the abdominal 

 swimmerets (Decapoda, Amphipoda, Isopoda). In this 

 position they are kept constantly aerated by the paddle- 

 like movements of these appendages. A similar habit is 

 found in the Pycnogonida, but here, curiously enough, it 

 is the male animal that carries the eggs, the latter being 

 transferred from the female after extrusion to a pair of special 

 appendages (ovigerous legs) present in the male. It is, 

 however, among shore fishes that the clearest cases of 

 parental care are found, and here, too, it is almost always the 

 male which assumes charge of the ova. 



In many shore fishes the eggs remain in the care of one 

 or both of the parents during the period between deposition 

 and hatching. In some cases the female dies after spawning, 

 and thus the male becomes parental. There is no reason to 

 read human nature into the conduct of the fish on such 

 occasions. On the other hand, that the presence of the 

 parent in the vicinity of the eggs is not merely fortuitous 

 is proved by the persistence with which the fish remains at 

 its post, even under conditions of considerable discomfort. 

 M'Intosh (1886) has described the behaviour of a male 

 " lumpsucker " {Cyclopterm) which was observed at St. 

 Andrews, about the middle of May, lying in a broad runlet 



