BREEDING 415 



offspring. Perhaps the more primitive form of parental fore- 

 sight is exhibited by those Fishes which, like the females of the 

 Salmonidae, make a furrow in the gravelly bottom of a running 

 stream for the reception of the eggs, and then cover them over 

 with a layer of gravel, or like the Siluroid Arius australis, of the 

 Burnett river in Queensland, which deposits its eggs in circular 

 excavations in the sandy bed of the river and covers them with 

 layers of large stones. But in neither case does it appear that 

 either the male or the female takes any further interest in the eggs 

 or in the young when hatched. Without actual nest-building, 

 or even the preparation of a place for their reception, the eggs 

 may be protected in various ways by the male. The common 

 British Gunnel or Butter-Fish (Pholis gunnellus) rolls its eggs 



■piG 236. — The Butter-Fish (Pholis gunnellus) coiling round a mass of eggs. 

 (From Cunniiigliam, after Holt.) 



into a rounded mass by coiling its body round them, the male 

 and female taking possession of them alternately. The little 

 clumps of eggs are then deposited in holes made by the boring 

 Mollusc, Pholas. Some British Blennies attach their eggs in a 

 single layer to the sides of cavities in rocks, or between stones, 

 where they are watched over by the male parent. The eggs of 

 the Lump-Sucker {Cyclopterus lumpus) are attached in masses to 

 rocks or to piles and guarded by the male, who aerates them l)y 

 keeping up a flow of water over the spawn through the action 

 of his pectoral fins. When hatched, the young fry cling to 

 the body of their watchful parent by their suckers. A more 

 decided approach to nest -building is exhibited by the Sand 

 Groby (Gobius mimttus). In this species the male scoops out 

 the sand from beneath an empty shell, generally that of a 

 Pecten, and the female deposits her adhesive eggs on the under 



