April, 1921. 



The Canadian Field-Xati kaijst. 



69 



not, Hs far as I am aware, appear recorded 

 from the State of New York. 



Lake (^)nstance is the. only locality near 

 Ottawa or in Ontario in which jayeyise has 

 been found. It occurs sparingly in two to 

 three feet of water on a muddy bottom at 

 the boat landing on the Vahey farm, near 

 Arraitage station. No other rnusculium 

 was collected in the lake, though several 

 doubtless occur. A large rough form of 

 Anodonta cataracta abounds, and a beau- 

 tiful variety of Lymnaea emarrjinata. 



26. MT'SCULIUM ROSACP^l'M Prime. 

 Shells of unusual size and beauty found 

 many .years ago in the bay at the east end 

 of the pond below the outlet of Meach Lake 

 were considered by Tyron to belong to 

 this species. L^nfortunately but few speci- 

 mens were collected, and the best of these 

 were distributed to correspondents. Re- 

 fuse from a saw mill destroyed the locality 

 as a habitat for delicate molluscs, and I 

 have been unable to visit the north side of 

 Meach Lake, where a warm muddy bay 

 would probabl}^ furnish the shell. 



In the pond on the former Cowley farm 

 in Nepean, about two hundred yards south 

 of the electric railway, and near the 

 boundary of the Ottawa Laud Company's 

 property', I collected in 1913 a quantity 

 of a large musculium which Dr. Sterki re- 

 gards as rosaceuni. I have visited the pond 

 nearly every year since but have not suc- 

 ceeded in again finding this shell. Other 

 species persist in surviving the total dry- 

 ing up of the pond in hot summers ; but this 

 seems to have become quite extinct. 



None of the shells found either in the 

 Laurentides or Nepean has a tint that 

 would justify the specific name applied by 

 Prime. It may be that the soft parts are 

 sometime rosy in color as is the case fre- 

 quently in Planorbis (Ditrorsus; but I have 

 not noticed that peculiarity in any shells 

 attributed to rosaceuni. 



Dr. Sterki states that this species has 

 been found from Maine to Virginia, and in 

 Ohio and Illinois as well as in Ontario. 



27. MUSCULRTM ROSACEUM FULI- 

 GINOSUM Sterki. A smaller and dif- 

 ferently colored shell, but witli similar out- 

 lines, occurs at the bridge on tiie Tavistock 

 Road, Britannia Highlands, and a mile or 

 so westward in Honeywell Creek, Avhere it 

 crosses the John Road. It is the only mus- 

 culium T have found in eitiier localitw 



While iiiclJDcd to regai-(| it as entitled tr* 

 specific rank, I yield to the vastly superior 

 experience and discrimination of Dr. Ster- 

 ki, and append his description from his 

 Preliminary Catalogue of North American 

 Sphacriidae (Ann. Carufj. Mus. X, 448.) 



21. Musculium rosuccum fuliginosum. 

 var. nov. 



Mussel small, rather short, subequipai-- 

 tite, moderately inflated. somewhat 

 "pinched" along the mai-gins; beaks near- 

 ly in the middle, narrow, somewhat pro- 

 minent, caljx'ulate; superior margin an- 

 gular at the beaks, its anterior and pos- 

 terior 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; sur- 

 face 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, glassv 

 transparent, with a marked grayish or 

 smok}^ 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, espe- 

 cially since all specimens are remarkably 

 uniform, but young and adolescent indi- 

 viduals reveal features of other forms of 

 M. rosaceuni. 



Habitat. Scott Graham Creek, Carleton 

 County, Ontario, collected by Mr. Justice 

 Latehford, 1911 and 1913. Specimens are 

 contained in his collection and in the Car- 

 negie Museum, Nos. 6,945 and 7,431. 

 Justice Latehford writes in November. 

 1913: "No. 2925 is quite common. I have 

 visited the creek at all seasons and never 

 found any larger shells than those which I 

 send; I therefore regard them— the larger 

 (mes — as full-grown.'' 



28. MrScrLIFM DECLIVE Sterki. 

 In Lake Gorman and in its outlet Brcn- 

 nan's Creek, near Hrudencll, in Renfrew, 

 was found a pretty little mu.sculium which 

 Dr.^ Sterki described as new (Nautilus. 

 XXV, 103). ^ It is about the .size of securis 

 and of a delicate yellow colour. Although 

 exceedingly frail, like the shell on the 

 Breton strand so beautifully described by 

 Tennyson, it is capable of withstand in'ir 

 the Maves and strong <Mnrcnts that sn 



