17 



The shell-fish were determined a number of years ago 

 by Dr. Dall and his assistants at the Smithsonian institution, 

 the list being as follows: — 



Unio undulatus ^ 



" \uteolus f Still living in lake Ontario. 



" gibbosus J 



" phaseohts \ ~ ..... . . . , ^ . , , , , 



" triannu* r Still living in lake Erie, but not reported 

 from lake Ontario. 



trigonus 

 coccineus 



" occidens 



" solidus 



" clavus 



" pyramidata 



Not known in the St. Lawrence system 

 of waters, but living farther south. 



Anodonta grandis. — Not reported from Canada. 

 Sphcerium rhomboideum. 

 " similis (?). 



" solidulum. 



" striatinum. 



" sulcatum. 



Pisidium adamsi. 



" compressum. 



novaboracense (?). 

 Pleurocera subulare. 

 " elevatum. 



" lewisi ( ?). 



Goniobasis depygis. 



" haldemane. 



Limncea decidiosa. 

 " elodes. 



bicarinatus. 

 Planorbis parvus. 

 Amnicola limosa. 

 " porata. 

 " sagana. 



ancillaria. 

 Physa heterostropha. 

 Succinea avara. 

 Bithinella obtusa. 

 Somatogyrus isogonus. 



