ACANTHOPTERYGII. 89 



pterus* Volitans,) found in the Mediterranean, is 

 about a foot in length : its long fins are beautifully 

 marked with blue. 



Gasterosteus^ the Stickleback. 



This active and pugnacious little fish, well known 

 to every truant schoolboy, is found not only in all our 

 rivers and brooks, but even in the sea all around our 

 coast. They are of small size, the dorsal spines free, 

 and not forming a fin, the body armed with bony 

 plates ; the ventral is merely a single spine ; the gill 

 rays are three. About half-a-dozen species are found 

 in our waters, of which the Rough-tailed Stickleback 

 (6r. Trachurusf) is one of the smallest, as well as 

 most abundant. So numerous are they, that in some 

 parts of the country they are used to manure the 

 land. Pennant states that a single man has taken 

 for this purpose nearly a hundred bushels a day, 

 for a considerable time. A correspondent of the 

 Magazine of Natural History, has given an amusing 

 relation of their habits, when put into a tub of 

 water. " When a few are first turned in, they 

 swim about in a shoal, apparently exploring their 

 new habitation. Suddenly one will take posses- 

 sion of a particular corner of the tub, or, as it 

 will sometimes happen, of the bottom, and will in- 

 stantly commence an attack upon his companions ; 

 and if any one of them ventures to oppose his 



* AaxrwXof , daktylos, a finger, and vrri(iov, pteron, a wing. 

 t Tao-T*)^, gaster, the belly, and, otrriov, osteon, a bone, 

 t/f, trachys, rough, and ou^a, cwra, the tail. 



