170 THE ANIMAL KINGDOM. 



minutely serrated edges making a powerful 'instrument 

 for rasping the surface of the sea-weed upon which the 

 Troclms feeds. 



The mouth (of the Trochus) has no upper horny plate, 

 and therefore probably needed this elaborately toothed 

 tongue. 



PALATE OF TROCHUS CRASSUS. 



Trochus Crassus is a variety of the same family, having 

 a large gray shell, and the tongue less beautiful. 



PALATE OF TROCHUS UMBILICATUS. 



TrocJms umbilicatus ; a smaller and more abundant shell, 

 also of gray colour. 



PALATE OF PERIWINKLE. 

 (Littorina.) 



The periwinkle is too well known to need description, 

 and the palate is very like that of the Trocftus Crassus. 



PALATE OF HALIOTIS, OR AUMER. 



The Haliotes is that beautiful univalve mollusc found in 

 the Channel Islands, under stones at low tide ; the fleshy 

 foot is sold in the market there, and highly esteemed as an 

 article of food, either stewed or fried in batter. The shell 

 is brought to England, and sold to manufacturers of 

 works inlaid with so-called mother-of-pearl, which is really 

 the beautiful interior of this shell. The palate is one of 

 the finest prepared for the microscope, and yet more com- 

 plicated than that of Trochus ziziphinus, which it resembles. 

 The central band here has rows of teeth, having nearly 

 straight edges instead of points ; there is on each side a 

 lateral band consisting of large teeth, shaped like those of 

 a shark ; and beyond this, again, another lateral band on 

 either side, composed of several rows of smaller teeth. (See 

 ' Carpenter on the Microscope/ p. 605.) 



The Haliotes are carnivorous as well as vegetarian, often 

 found feeding on dead bodies. 



