THE STICKLEBACK BUILDING ITS NEST. 351 



it is bright crimson, on the upper part of its body 

 various tints of green prevail ; while in the pond 

 specimen no red colour is visible at all, but only 

 white blended with green. 



In addition to Oasterosteus aculeatus, whom we 

 have above alluded to, there is another species, G. 

 spinachia, or Fiffceen-Spined Stickleback, which is 

 also an inhabitant of rock-pools by the sea-shore, 

 but unlike the first-mentioned, is never found in fresh 

 water. Both species possess one peculiarity in com- 

 mon, a description of which will form an appropriate 

 conclusion to this chapter. I allude to their nest- 

 building habits, which has only of late years been 

 proved to exist, although Aristotle has recorded the 

 same fact regarding a fish (Phycis) in the Mediter- 

 ranean Sea, which was known to make a nest and 

 deposit its spawn therein. 



The duties of mason and architect are invariably 

 undertaken by the male Stickleback. His materials 

 are of course very limited, still his labours are skil- 

 fully and even artistically performed. Having chosen 

 a suitable spot as a foundation for his house, he collects 

 some delicate sea-weeds, gravel and sand, and with 

 these materials, aided by a glutinous fluid which is 

 given off from his body, the house is built. When 

 completed, and not before, he seeks out his mate, and 

 invites her to take possession of her newly formed 

 home. If she shows any affectation or coquetishness, 

 he does not hesitate to nip hold of her tail, and urge 



