106 THE NAUTILUS. 



Sph cerium simile Say. Generally distributed. 



Spli cerium striatinum Lam. Fish River and Saint John River at 

 Fort Kent. 



Sphcerium rliomboideinn Say. Fine specimen in Gelot Lake, New 

 Sweden, and all the smaller lakes of the Little Madawoska river 

 system. 



Calyculina secnris Prime. Aroostook River. 



Calyculina sccuris cardissa Prime. Square Lake and other localities. 



Pisidium nbditinm Ilald. Common. 



Pisidiinn adamsi Prime. Cross Lake Inlet. 



Pisidium cequilaterale Prime. Portage Lake. Little Madawaska 

 River. 



Pisidiinn coitfortum Prime. Hear Mud Lake, Perham and West- 

 moreland. 



Pisidiinn <-nmpr<_>sxinn Prime. Generally abundant. 



Pisidiinn i'cri-injini'iim Prime. Fogelin Lake, New Sweden and 

 many other localities. 



risidiiim f(ill<ix Sterki. Aroostook River. 



Pisidiinn fiillax boreale Sterki. Aroostook River at Caribou and 

 Little Madawaska River, New Sweden. 



Pisidiinn in/Hum Held. South branch Caribou Stream, Woodland 

 and Sawyer's Brook, Castle, Hill. 



Pisi<liinn mcdiaiunn iitiinitiini Sterki. Racket's Mill Brook, a 

 tributary of Caribou Stream in the northern part of Woodland. 



Pisidliun. pdii'pi'rciihini Sterki. Little Madawaska River. 



Pisidhim piniperailiini i/y/aiideri Sterki. Dredged in Portage Lake. 



Plsidiinn politnm Sterki. Portage Lake and Cross Lake. 



Pisidimn puiictatum Sterki. Portage Lake, Little Madawaska 

 River. 



Pisidiinn roperi Sterki. Johnson Brook on the Fort Kent road 

 and north of Perham. 



Pisidiinn sph'ndidiihnii Sterki. Barren Brook, Caribou and many 

 other localities. 



Pisidium ventm'cosum Prime. Barren Brook, Caribou. 



Pisidium variabile Prime. Common everywhere. 



Pisidiinn walkeri Sterki. Barren Brook, Caribou. 



Pisidiinn indkeri mainense Sterki. Racket's Mill Brook, Wood- 

 la'nd and many other localities. 



