1911] The Ottawa Naturalist. 19 



CONCHOLOGICAL NOTES. 



The fresh water pearl mussel, Margitana mar gar hi] era, was 

 recently collected by one of my sons in the Ste. Croix River 

 near St. Stephen, New Brunswick. The shells are small in com- 

 parison with specimens from the St. Lawrence Valley, and none 

 contained pearls. Larger, and especially cortorted, shells, from 

 rapid water would no doubt produce, as such shell do in other 

 countries, the concretions which are sometimes so beautiful and 

 highly prized. In Saxony a profitable fishery of this mussel has 

 been carried on as a state enterprise for hundreds of vears. 

 Shells presenting the characters known to indicate the true 

 pearl-bearers are carefully opened with a wooden wedge, 

 searched and if found barren returned uninjured to the streams, 

 from which they are again taken in a year or two. 



A shell of the same genus, not previously reported from 

 Ontario, was recently found in the Winnipeg River at Kenora, 

 below the falls. It is the flat pearl shell, Margaritana com- 

 planata, abundant throughout the Mississippi basin, and extend- 

 ing northward into Manitoba. 



The rare Planorbis corpulentus, originally described in 1830 

 by Thomas Say, from the Lake of the Woods and Rainy Lake, 

 and the still rarer Lymncea binneyi, Tryon, were found near Fort 

 Frances. Tryon's shell has unfortunately shared the fate to 

 which his Planorbis binneyi was so long subjected. It was 

 thought to be a form of Lymncea emarginata, as PL binneyi was 

 though to be either a form of trivolvis or Say's PL corpulentus. 

 L. binneyi is a beautiful, large and distinct species, of which I 

 hope soon to see a plate in the Naturalist. PL binneyi is the 

 very large Planorbis which occurs in the Rideau just west of 

 Billing's Bridge, especially on the north shore, above the rapids. 

 I have found it at several other points in the same river; in the 

 Rideau Canal, at the Exhibition Grounds, in Meach Lake one 

 specimen only and in Giroux Lake, near Cobalt. In certain 

 localities in the Rideau Canal and River it is associated with 

 PL trivolvis, but it does not seem to occur in the Ottawa, where 

 PL trivolvis is in everv bay a common shell. 



The numerous specimens of PL corpulentus which Say 

 collected were lost* and the shell which he figures, Plate 15, Fig. 

 9, was procured from Dr. Bigsby. My shells were collected 

 near Kettle Falls, at the east end of Rainy Lake. Many are 

 larger than those measured by Say. He rightly describes it as 

 "closely allied to PL trivolvis but much less rounded on the sides 

 of the whorls. The carinae are more prominent, the upper side 



Appendix to Narrative of Long's Expedition, London, 1825, page 10. 



