THE STICKLEBACKS. 355 



in length and is furnished with spines which it uses with great 

 effect when fighting with its enemies. 



The stickle- ^ r - J onn Stark who experimented with some 

 back and the sticklebacks and leeches some years ago gives the 



following description of his experiences. 

 " On putting the leeches into the water, the stickleback 

 darted 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 in 

 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 

 glass ; but again and again the attack was repeated, till the 

 poor leech became exhausted, and ceased to attempt holding 

 itself by its disc. The stickleback then seized it by the head 

 in a proper position for swallowing, and after a few gulps the 

 leech disappeared. The flattened leech being of an oval form, 

 and having a hard skin, was not attacked, unless when very 

 young, and small ; and leeches of the other species when pretty 

 well grown, or larger than himself when expanded, were killed 

 in the manner above mentioned, but not swallowed. In one 

 of his attempts to seize a leech, the stickleback having got it 

 by the tail, the animal curled back and fixed its disc upon his 

 snout. The efforts of the stickleback to rid himself of this en- 

 cumbrance were amusing. He let go his hold of the leech, 

 which then hung over his mouth, and darting at the bottom 

 and sides of the glass with all his strength, endeavoured to rub 



