74 WESTERN SERIES OF READERS. 



If you examine the organs of a mussel, you will 

 find that the flesh is of a bright orange color. 

 There are four gills, two on each side, looking like 

 delicate ribbons. These gills are the organs by 

 which it breathes, and they also help gather its 

 food. The outside of the shell is covered with a 

 horny skin, brown or black in color; this is apt 



Figure 28. 



to peel off from the older parts of the shell, show- 

 ing the purple and white beneath. 



Mussels are sometimes gathered by men for food, 

 and they make excellent bait for fishing. It some- 

 times happens, however, that their flesh seems to be 

 poisonous to men, and this fact should make one 

 careful about eating too many, until they have been 

 tested. At most times they have a delicious flavor. 



Besides the common mussel, there are several 

 others which have similar habits. One of these 

 lives in San Francisco Bay, and attaches itself 

 to the piles which support the wharves. Its 

 shells are small and smooth. Another kind is 

 known as the Horse-mussel. One of these is 



