132 



In the past year, as in the year pi-evious, the water in the Ottawa 

 never fell so low as to enable us to collect any of the fine unios which 

 are known to occur down the rivei*. 



Undoubted specimens of Sphcer'min securis, Prime, were obtained 

 in the culvert which crosses St. Louis Dam. On Mr. Hei'on's list this 

 species is marked with a query. 



Planorhls bicarinatus, Say, in the typical form was found on the 

 right shore of the Rideau in the rapids near Hartweli's Locks. A small 

 variety with the keels less developed and with coarse wrinkles was 

 found in the pond east of the Bank Street Road near Billings' Bridge, 

 and in brooks in Hull and Masham. Meech's Lake afforded tivo shells 

 of this s}>ecies of much greater size than any previously found, but of 

 the typical form. The measurements of the lai'ger shell are as follows : 

 Greater dia. 0.83 in., lesser dia. 0.64 in., height 0.52 in. Both shells 

 were unfortunately dead. They were found near the outlet of the 

 lake. Living specimens will probably be had higher up the lake — a 

 locality still unknown to us and worthy of a visit. 



Very fine Limncea columella, Say, were found in the early part of 

 November in the bay above Mason's mill, at Mechanicsville. One 

 specimen clung with such tenacity to the log on which it was observed 

 that, while the empty shell came away in the collector's fingers, the 

 animal itself remained adhering to its foothold. 



On the 13th October a good find of Campeloma decisum, Say, was 

 made in McKay's Bay, New Edinburgh. The shells, though not of so 

 bright a green as those of the Rideau, are nevex'theless of good colour, 

 very large, and beautifully clean. 



Two weeks later the same locality was visited, when no living 

 shells were to be found, but numbers of fresh dead specimens were 

 observed with the peristome broken where thinnest and portions of the 

 animal extracted. Whether this was done by niuskrats or birds could 

 not be ascertained. 



An effort was made during the past year to collect from as many 

 different localities as were accessible large sets of our commonest shells, 

 such as Limncea stagnalis, L. palustris, Physa helerostropha and Pla- 

 norhis trivolvis. Many forms of these protean species have been col- 



