NATURAL HISTORY. 

 Family, Mytilidse. (Gr. Mtm/lof, a Mussel.) 



Edulis (Lat. edible), the Edible Mussel 



The river mussels occasionally produce pearls of some value. 

 The nacre of these mussels is of a beautiful azure blue. 



Order, CIRRHOPODA.(G\\ Hevrt, five; lAaopa, a plate.) 



PENTALASMIS. 



Anatifera (Lat. Goose-bearing'), the Bernicle. 



At first sight, the Bernicle bears a close resemblance to a 

 mussel-shell fixed to a long stem. On a closer examination, 

 however, the difference is at once apparent. The shell is in 

 fact composed of five pieces, and through the aperture of the 



