506 FISHES. 



sometimes swarms in prodigious numbers. Pennant states 

 that at Spalding, in Lincolnshire, there was once in seven 

 years amazing shoals, which appear in the Welland, coming 

 up the river in the form of a vast column. The quantity may, 

 perhaps, he conceived from the fact that a man employed in 

 collecting them, gained, for a considerable time, four shillings 

 a-day by selling them at the rate of a halfpenny a bushel. 

 Costa, who studied the manners of these small fishes, relates 

 that, on the approach of spawning time, the male builds 

 a nest of stalks of grass and other matters in a hollow* 

 of the l)ottom, a little above three inches wide and about 

 six inches and a half deep, creeping over the materials on 

 his belly, and cementing them with the mucus that exudes 

 from his skin. The bottom of the nest is first laid, tlien 

 the sides are raised, and lastly the top is covered over. A 

 small hole is left on one side for an entrance. When the 

 erection is complete, he seeks out a female, and conduct- 

 ing her, Costa says, with many caresses, to the nest, intro- 

 duces her by the door into the chamber. In a few minutes 

 she has laid two or three eggs, after which she bores a hole 

 on the opposite side of the nest to that by which she 

 entered, and makes her escape. The nest has now two doors, 

 and the eggs are exposed to the cool stream of water, which, 

 entering by one door flows out at the other. Next day the 

 male goes again in quest of a female, and sometimes brings 

 back the same, sometimes finds a new mate. This is repeated 

 until the nest contains a considerable number of eggs, and 

 each time the male rubs his side against the female and 

 passes over the eggs. Next the male watches a whole month 

 over his treasure, defending it stoutly against all invaders, 

 and especially against his wives, who have a great desire to 

 get at the eggs. When the young are hatched and able to 

 do for themselves his cares cease. 



The Sea-Stickleback {G. sjnnachia) is likewise a nest 



