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THE BRITISH COLUMBIAN OYSTER 

 {Ostrea lurida, Carpenter) 



Description. — Before making any headway in the study of the trans- 

 planted Prince Edward Island oysters I had begun to gather information 

 on the occurrence, distribution, size, shape, colour, structure, breeding, 

 etc., of the native British Columbian species. This oyster had been noticed 

 in a faunistic way by Carpenter (Suppl. Rep. Brit. Assoc. 1863, p. 645), 

 Dawson, Whiteaves, Newcombe, Taylor, and others, and more closely 

 with regard to its mode of breeding by Prince (Peculiarities in the Breeding 

 of Oysters, Special Reports 1895, Ottawa) . It occurs from Queen Charlotte 

 sound south-ward along the coasts and coastal waters of British Columbia, 

 Washington, Oregon, and California. In the gulf of California occur a 

 large species {Ostrea iridescens) and one {Ostrea palumea) or two small 

 species, all of which have received little attention. 



In Departure bay the British Columbian oyster is not common, but a 

 few small specimens may be found under stones exposed about one hour 

 above low-water mark in front of the Canadian Pacific Railway cable 

 house, and usually so broadly and solidly attached (with the left valve 

 against the under side of the stone, i.e., uppermost in the natural position) 

 that it is scarcely possible to separate them without destroying the attached 

 valve. A few occur under like conditions just inwards from the far point 

 at Hammond bay. On the extensive flats exposed at low tide at the 

 upper ends of Nanoose bay and Oyster harbour they occur by thousands, 

 free on the surface, and more or less spotted with barnacles. 



Good specimens reach two inches in length by an inch and a half in 

 breadth, with a straight dorsal and a semi-circular ventral margin. The 

 right, upper, or smaller valve is nearly flat or but little convex, and fits 

 into the margin of the left, lower, larger, and very convex valve, the greater 

 part of the ventral and posterior margin being scalloped, while the left 

 valve may be fluted and knobbed, presenting an appearance very much re- 

 sembling small oysters of the short or rounder variety at Ram island, 

 Malpeque. The colour is usually dark (those under stones lighter) with 

 the older parts weathered grayish, and the umbonal region of the left 

 valve is often attached to a small stone or another oyster or bears a scar. 

 Internally the shell is extensively pigmented, dark with small bands or 

 blotches of lighter pearl, while the muscle scar is rather lighter and banded. 

 The mantle is broadly margined Avith dark, which may also creep up on to 

 the abdomen. 



