216 SHELLS AND MOLLUSCOUS ANIMALS. 



the only certain character is afforded by the 

 number of little notches on the sides of the valves, 

 and these cannot be ascertained but by taking the 

 shell to pieces. The tufted canoe-shell (Chiton 



fascicularis) is one of the 

 commonest kinds, and 

 very plentiful on our 

 southern coasts, and may 

 be known by the little 

 tufts of hair around the 

 margin of the shell. The 

 whole surface of the valves, when seen through a 

 microscope, appears to be covered with fish-like 

 scales, excepting the beak, which is smooth, and 

 of a yellower colour than the other part. The 

 Emarginate canoe-shell ( Chiton marginatus) is also 

 a frequent species, and is of a dingy brown or 

 reddish colour. These shell-fish are much larger 

 in hot countries. 



Sometimes, when wandering among the rocks 

 near the low water mark, we find, among the 

 groups of sea -weed, that singular molluscous 

 animal, the Sea-hare (Aphysia depilans). It is a 

 kind of soft slug, of a blackish colour, tinged with 



Eurple, not of an attractive appearance, and 

 aving, besides, an unpleasant odour. A sub- 

 stance exudes from its skin, which in days of 

 superstition was believed to cause the hair to fall 

 off from the person who only touched it. The 

 ancient writers told, that from it was produced 

 the poison by which tyrants destroyed their 

 victims, and relate that Nero mixed it with the 

 food of those whom he hated, and that Titus used 

 it to destroy Domitian. But the charges of 

 antipathy to man, so repeatedly urged by them 



