FRESH-WATER MUSSELS. 27 



Tlie beach-cockle deposits its eggs in a broad ribbon of 

 sand cemented together, looking very much like a deep 

 saucer, with the bottom broken out, and the side separated 

 (Fig. 3i). 



FIG. 83. EGG-CAPSULES OF COMMON COCKLE. (A shell of the animal which produces these 

 capsules is shown in the upper central figure of Fig. 26.) 



This ribbon is elastic when wet, and, if it is held up to 

 the light, the little transparent spaces for the eggs will be 

 plainly seen. 



FIG. 84. EGG-RIRDON OF BEACH-COCKLE (the shell of which is shown in the lower 



right-hand figure of Fig. 26). 



CHAPTEE Y. 



FKESH-WATER MUSSELS. 



26. LOOKING over our fresh- water shells again, we find 

 many that are known as mussels, or clams. These shells are 

 common everywhere along the margins of brooks, rivers, and 

 lakes. The musk-rats feed upon the soft parts of the mus- 



