94 The Ottawa Naturalist. [November 



mollusca. Several of the species and varieties now described for the 

 first time are from the vicinity of Ottawa, and may be of interest to 

 members of the Field-Naturalists' Club, who wish to spend a little of 

 their leisure riding a delightful if neglected hobby. An hour or two 

 devoted to any elementary work on zoology, dealing as nearly all do 

 with the mollusca, will enable any intelligent student to understand 

 Dr. Sterki's descriptions which will then be found to be full, clear 

 and distinctive, though necessarily technical. 



The shells themselves occur in every stream around the city. A 

 kitchen bowl-strainer, of coarse mesh procurable at a cost of a few 

 cents makes an excellent dredge for the larger species. In the 

 shallows on the right bank of the Rideau Canal, above the by-wash at 

 Hartwell's Locks, hundreds of fine specimens, mainly Musculium 

 transversum, may be collected in a few minutes; and this and other 

 species may be found without a dredge by turning over small boulders 

 in the Rideau River, in the rapids near Billings' Bridge. Every 

 depression in which water gathers in our deciduous woods contains the 

 beautiful little Sphacrium Occident ale, a species capable of living 

 through long periods of drought; and in late summer the northern 

 shores of Duck Island, just at the water's edge, are littered with 

 myriads of small bivalves, mainly a variety of Sphaerium striatinum, 

 or, perhaps, a species as yet undescribed. More and more material is 

 required. It is with the hope of stimulating interest, and in order to 

 render accessible to members of the Club descriptions not otherwise 

 readily available that, with Dr. Sterki's permission, the following 

 extracts are reprinted from his catalogue: 



21. Musculium rosaceum fuligiosum var. nov. 



Mussel small, rather short, subequipartite, moderately inflated, 

 somewhat "pinched" along the margin; beaks nearly in the middle, 

 narrow, somewhat prominent, calyculate; superior margin angular at 

 the beaks, its anterior and posterior parts straight or nearly so, equally 

 sloping; supero-anterior and posterior slopes, or truncations, well 

 marked, nearly straight, the posterior longer and steeper, nearly at 

 right angle with the longitudinal axis, anterior and posterior ends 

 rounded; inferior margin moderately curved; surface shining and 

 with a silky gloss derived from very narrow, membranous, scaly pro- 

 jections of the periostracum on the fine concentric striae; shell very 

 thin, glassy transparent, with a marked grayish or smoky hue. 



The largest specimen measures: Long. 7; alt. 6; diam. 3.8 mm. 



The mussel is striking in appearance, and at first sight seems to 

 be distinct, especially since all specimens are remarkably uniform, 

 but young and adolescent individuals reveal features of other forms 

 of M. rosaceum. 



Habitat. Scott Graham Creek, Carleton County, Ontario, col- 

 lected by Mr. Justice Latchford, 1911 and 1913. Specimens are 



