136 Descriptive Zoology. 



Limpets. Along the shore there are to be found gastro- 

 pods with low conical shells, clinging close to the surface 

 of the rocks. They may be scraped off by a quick motion 

 with a dull knife, but if they are first alarmed they draw down 

 and adhere so firmly to the rock that one is likely to break 

 the shell in the attempt to dislodge them. The keyhole 

 limpet is so named from the shape of the hole at the apex. 



The Ear-shell or Abalone. Closely related to the limpets 

 is the " ear-shell " found on the California coast. There is 



FIG. 92. ABALONE OR EAR-SHELL. 



Furnishes mother-of pearl for inlaid work. 



FIG. 91. LIMPET. 



Surface view and side view. FlG. 93. RED CHITON (kl'tSn). 



a row of perforations near one margin of the shell, through 

 which tentacles project. The interior of the shell is pearly 

 and of beautifully variegated color. It is known as " aba- 

 lone," and is much used for inlaid work. 



A Multivalved Mollusk. Chiton is a very peculiar 

 marine mollusk. It is low and flat, creeping like the lim- 

 pets. But the shell consists of a series of eight pieces over- 

 lapping one another from the anterior to the posterior end. 

 The animal is completely symmetrical, both internally and 

 externally (Fig. 93). 



