. The Canadian field-naturalist. N ovember, 1919] The Canadian Field-Naturalist 85 delightful impressions that may be derived from flowers and birds, and the many strange four and six-footed creatures that he will encounter on his rambles in places seldom frequented by man. A very fine form of 5. sulcatum occurs on the Scott Graham farm in Nepean, now called Bri- tannia Highlands. In dry seasons the narrow bot- tom of the stream lying about halfway between Carling Avenue and the Grand Trunk railway is exposed for some distance west of the boundary of the Shouldis farm. The shell may then be ea
. The Canadian field-naturalist. N ovember, 1919] The Canadian Field-Naturalist 85 delightful impressions that may be derived from flowers and birds, and the many strange four and six-footed creatures that he will encounter on his rambles in places seldom frequented by man. A very fine form of 5. sulcatum occurs on the Scott Graham farm in Nepean, now called Bri- tannia Highlands. In dry seasons the narrow bot- tom of the stream lying about halfway between Carling Avenue and the Grand Trunk railway is exposed for some distance west of the boundary of the Shouldis farm. The shell may then be easily found in considerable numbers. At other times collecting is slew and difficult, even though the collector is equipped with a good dredge, and— what are indispensable in such localities—rubber boots. This stream is again productive near its outlet into the Ottawa below the Deschenes rapids. conditions of environment. In fact nothing is so wonderful in nature as the adherence to type of every organized being properly regarded as a species. More interest is, however, manifested in departures from the normal than in persistence of type, just as variant races of men, like the giant Patagonians and pygmy Papuans, commonly at- tract more attention than races of ordinary stature. Variations from the usual form of 5. sulcatum are few and limited. One is found in Bond lake, near Toronto. Another, which is well marked and con- stant, occurs in Masham, north of Ottawa, and, notably, in Lake Gorman, near Brudenell, in the county of Renfrew, at an elevation of about eleven hundred feet above sea level. Dr. Sterki thinks it entitled to rank as a variety and calls it palmaiuiu.' He describes it as smaller OS. aa^^ a rp - ot'-. Vh —Anterior adductor —Ant. retractor-pedis muscle. ar.^Auriele. b.—Byssal gland rudiment. bs.—Branchial sii)hon. eg.—Cerebral ganglion. cs.—Cloacal siphon. f.—Foot, ig.—Inner gill. 1.—Liver. Fair specimens are obtainable in sh
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Keywords: ., bookauthorottawafieldnaturalist, bookcentury1900, bookdecade1910
