On the Habits and Food of the Stickleback. 77 



the last summer, and fed them at first with earth-worms, 

 maggots, and occasionally the small house-fly, which, how- 

 ever; did not seem to be relished. Afterwards, at my sug- 

 gestion, young leeches were brought from the ditch m which 

 the sticklebacks were caught, as being more likely, with the 

 larva; of aquatic insects, to form part of their natural supply, 

 than the food which was submitted to their choice. These 

 were found to be preferred to all other aliment, and for a 

 month at least they had scarcely any other food. The spe- 

 cies of leeches procured were the Hirudo sangmsuga, the H. 

 vulgaris, and the H. complanata. To ascertain what size of 

 leech would be swallowed, a male stickleback, of about an 

 inch and three quarters in length was selected and put in a 

 large tumbler on a mantel-piece, where its mode of attacking 

 and devouring its prey formed a source of amusement to the 



children for weeks. . 



On putting the leeches into the water, the stickleback dart- 

 ed round the tumbler with lively motions, till it found a leech 

 detached, and in a proper situation for being seized When 

 the leech was very small, say about half an inch m length, it 

 was often swallowed at once, before it reached the bottom of 

 the vessel ; but when a larger one, about an inch or an inch 

 and a-half in length in its expanded state, was put in, and 

 had fastened itself by its mouth to the glass the efforts of 

 the stickleback to seize and tear it from its hold were inces- 

 sant, and never failed to succeed. It darted at the loose ex- 

 tremity, or, when both ends were fastened, at the curve in its 

 middle, seized it in its mouth, rose to near the surface and 

 after a hearty shake (such as a dog would give a rat) let it 

 drop The leech, who evidently wished to avoid its enemy, 

 upon its release again attached itself by its mouth to the 

 class ; but again and again the attack was repeated till the 

 ;„orieechbe g came exhausted, and ceased to attempt holding 

 iself by its disc. The stickleback then seized it by the 

 ad in a proper position for swallowing, and after a few 

 X the leech disappeared. The H. complanata, being of 

 an ovate form, and having a hard skin, was not attacked 

 Less when very young, and scarcely two or three lines in 



