314 WEST COAST SHELLS 



happy creatures that love to live in cool, clear 

 water, where the green algie grow and the banks 

 are edged with ferns and water-weeds. I gath- 

 ered them in abundance from a little stream of 

 most delicious water that bursts out from .the base 

 of a dry hill, just north of the village of Sisson in 

 northern California. Evidently there are concealed 

 passages leading from the dry hill up to the great 

 snow-helds on the flanks of Mount Shasta, for after 

 you have climbed far up beyond the timber-line and 

 are walking over the great expanses of white you 

 can hear the gurgling of little streams under your 

 feet and you know that the melting drifts are sinking 

 down into the bosom of the mountain to reappear 

 among the groves and meadows that mark the boun- 

 daries of the Upper Sacramento." 



THE LAKE AND FLOOD SHELLS 



{A?nnicolidd::) 



These tiny fellows are operculate as are also the 

 PlcuroceridiE and succeeding families. They have 

 a closed or nearly closed umbilicus and are usually 

 greenish or brownish. Some live in streams and 

 some in lakes and springs. 



Amnicola micrococcus^ Pilsbry, the Desert Amni- 

 cola, PL III, Fig. 13, is a small species of the desert 

 region. It has a chunky green-brown shell with 

 inflated whorls and a closed umbilicus. It is about 

 the size of a capital (). Found in springs in the 

 Nevada System. 



Valudcstrina longinqua^ Gould, the Western Palu- 

 destrina, PI. Ill, Fig. 11, is about the size of a 



