70 NATURAL HISTORY. 



is rather oval, turbinated only on the posterior portion, 

 and furnished on the outside with projecting folds (plicae) 

 and warts or knobs. Along the columella or right hand 

 border is a series of holes, through which the water 

 reaches. Its length is above three inches, its breadth 

 two, internally covered by a layer of mother-of-pearl, 

 and on the outside is of a grayish-green color striped 

 with red. It is found on almost every sea coast, where 

 it clings to the rocks, adhering to them closely. It is 

 eatable. 



The Knee Pan (patella vulgata). All the patella 

 have a broad-based, pan-like shell, without a vertebral 

 spine, that covers the whole body of the broad, fleshy 

 animal within, are found on every sea coast, and adhere 

 so closely to the rocks, that it is necessary to detach 

 them with a knife. The most common is pearl-like in- 

 side, two inches long and two high ; the shell is whitish- 

 gray on the outside, surrounded by four rows of leaflets 

 or fringes, which are russet-colored. This species, of 

 which there are many varieties, are used as food. 



The Sea Hares (aplysia depilans) have, instead of a 

 shell, a horny plate or fold which is covered by the 

 mantle, was. well known to the ancients, who gave it the 

 name of sea hare. It has an unpleasant odor, and is 

 supposed to possess poisonous qualities. Its form is 

 singular, being drawn up together, so that it somewhat 

 resembles a young -hare. Its color is a dirty brown ; 

 length from six to eight inches, thickness three. The 

 body is ornamented with spots of a beautiful purple 

 color ; if pressed or crushed, a reddish-colored liquid is 

 poured out, which is of so acrid a nature that the hand 

 which it touches, will swell immediately, and if, by any 

 means, a drop of this fluid is brought in contact with the 



