52 The Ottawa Naturalist. [June-July 



others undoubtedly occur. In the Rideau canal for instance, 

 while it is impossible to distinguish two species among the large 

 Anodontae found there, a series of young shells, such as may 

 easily be obtained in the little bay on the left side of the canal 

 immediately above Hartwell's Locks, demonstrates the pres- 

 ence of two species — one certainly cataracta Say, and the other 

 probably implicata Say. I used the word "probably" because 

 I do not know what the 5^oung of implicata are like, and I know 

 of no satisfactory description. Stimpson in his Descriptive 

 Catalogue of the Naiades (Detroit, 1914) says "their sculpture 

 consists of straight bars running parallel with the linge line, or 

 they may be slightly curved and sometimes a little corrugated, ' ' — 

 which seems to me a confounding of two species. The beak 

 sculpture of the Unionidae is — I have observed — for any species 

 invariable. A. cataracta in every stage of growth has been 

 collected by the writer in at least fifty localities in Quebec and 

 Ontario — from the lakes in the Laurentides to Toronto Bay, 

 where it occurs with A . grandis Say — and the undulations of the 

 beaks, when they could be made out, were in every case the same. 



In addition to the three species named, man}^ others occur in 

 the Ottawa valle}^, but, until large series of shells are procured 

 in every stage of growth, they cannot be determined, or, if new, 

 described. It is really not more difficult to collect the young 

 of mussels than to collect other small bivalves ; that they cannot 

 be seen should not prevent a search for them — nor the fact that 

 they are often far less numerous than adults. A wire bowl 

 .strainer with a suitable handle will often produce the most 

 astonishing returns from places that appear quite barren of 

 mollusc an life. 



Tjll the Missinaibi is visited by an experienced collector, the 

 Anodontae from it can be regarded as only probably new. 



Among the Missinaibi shells are two medium sized examples 

 of Unio pressus Lea, now designated Symphonota compressa 

 Lea. In addition of the localities mentioned in previous notes — 

 the. Rideau at Strathcona Park and Paquette's Rapids, near 

 Pembroke and Moore's Creek on the A3dmer Road, and a brook 

 crossing the Opeongo Road, near Foymount, in the County of 

 Renfrew, afford this attractive little mussel. It has been 

 recorded from as far north as the Montreal river near Sault Ste. 

 Marie (Stimpson, Des. Cat. 483) but has not hitherto been known 

 to exist in the Hudson Bav drainage. 



L. 



