PIERCED SHELLS AND CHITONS 



249 



mens have been obtained from the Bay of Mon- 

 terey, but it is found in very few cabinets. The shell 



Fig. 247 (*) 



is large, strong, grayish-v/hite in color, and it has 

 many radiating ribs. Note the trough which extends 

 from the apex to the margin, and which passes be- 

 tween the heels of the horseshoe-shaped muscle-scar. 

 The shell is 51 mm. in length and 13 mm. in height. 



Figure 248 represents the 

 shell of one of our most common 

 species, Fisssurella volcano^ Rve., 

 the Volcano-shell. Dead shells 

 are abundant and attractive, and 

 living specimens, with yellow 

 foot and red-striped mantle, may often be found on 

 the rocks at low tide. The shell is about an inch in 

 length, and is oblong conical in form; the red stripes 

 on its sides, running down from the small, oblong 

 hole at the top, suggests streams of red-hot lava 

 issuing from the crater of a volcano. The coloring 



Fig. 248 



