302 WEST COAST SHELLS 



was covered with a glossy mahogany epidermis ex- 

 cept at the umbos, where the sand grains had worn 

 nearly through the stout shell. Opening it with my 

 knife, I beheld a lining of an orange as brilliant as 

 an Eschscholtzia. Dropping it into my bag I con- 

 tinued my wading. Another I Opening this I found 

 it a beautiful royal purple. A third was an exquisite 

 pale blue, a blue no artist might duplicate. As I 

 look at the faded shells now I think how elusive is 

 nature and how impossible to more than imitate her. 



The shell is elliptical with one central tooth at 

 the umbo in the right valve, and two in the left. 

 In some specimens these are small, in others large 

 and there is a trace of lateral teeth. It is the only 

 species on the Pacihc Slope that has more than a 

 suggestion of teeth. The pearly interior is purple, 

 orange, blue, pink, or green. The color is very fugi- 

 tive. The shells of this and other Naiads should be 

 rubbed with a very little vaseline and wiped dry 

 with a bit of cotton. This will prevent them from 

 cracking and preserve the color in a measure if kept 

 in the dark. 



This species delights in clear, swift streams where 

 it lies partly buried in the gravel or sand bottom. 

 Found in the Columbia, Klamath, Utah, Nevada, 

 and a few places in the Coast Range System, also in 

 New England, Europe and Asia. 



Anodonta cygnea^ Linne {^A. oregoncnsis)^ the 

 Swan Naiad, Plate II, Fig. 7, with its numerous 

 forms, is one of the most common, widely dis- 

 tributed, and variable river mussels, which is saying 



