170 ACANTHOPTERYGII. GOBIAD^. 



we were led to speak of the nest-making instinct 

 of a species of Stickleback, and extracted some 

 particulars from a communication of great interest 

 made to the Royal Institution of Cornwall. In 

 the same paper the author gave an account of 

 two other fish-nests, one of which was found to 

 belong to the present species. *' It may perhaps 

 be doubted whether the term nest is strictly ap- 

 plicable to this, as the fish merely makes use of 

 a natural cavity in the rock, in which the ova 

 are deposited, and remain adherent ; but as it 

 shows a deviation from what has been considered 

 as the usual mode of spawning in fish, it may 

 be briefly noticed. The cavities selected are 

 almost always nearer the low than high water- 

 mark; they have generally rather narrow open- 

 ings, and the roofs are smooth, or are at least 

 not much broken by fissures. On the roofs and 

 sides of such cavities the ova are deposited, and 

 thickly arranged, looking as if they were vaulted 

 with a pavement of round stones. As the ova 

 are of a beautiful and bright amber-colour, with 

 a highly polished surface, they have a very bril- 

 liant appearance as the light falls upon them in 

 their dark recess. They are semi-circular in 

 form, and about one-tenth of an inch in diameter. 

 Having succeeded in hatching them, I proved 

 them to belong to the Common Shanny {Blennius 

 pholis). This opinion of their character has been 

 repeatedly confirmed, as it is the habit of this 

 fish to retire beneath stones, or to crevices of the 

 rock, during the recess of the tide, where they 

 remain dry until the sea returns. By enlarging 

 the openings of the cavities, I have generally 

 succeeded in capturing the adult animal at the 



