86 THE ECONOMIC MOLLUSCA OF ACADIA 



hundred dollars, and another of similar shape in St. John for 

 the same price." These, of course, are very exceptional 

 instances, the great majority of those found being small, of 

 poor shape and of bad color. It must be borne in mind, in 

 considering these facts, that a great amount of persevering, 

 labor and considerable skill is required to obtain such results. 

 Its returns are too uncertain to allow the fishery ever to be of 

 much economic value. 



Works of Reference. 



Pearls. By F, W. Rudler. Encyclopaedia Britannica, 9th 



Ed., Vol. XVIIL, pp. 44G-448. 

 Pearls and Pearl-fisheries. By TV. H. Dall. American 



Naturalist, Vol. XVIL, 1883. 



18. Cardium Islandicnm Linnasus, 

 Cardium ciliatum Fabr. 

 Cockle. 



[Cardium, heart-shaped; Islandicum, Icelandic]. 



Distribution", {a) General; — Near low-water mark to 

 fifty fathoms. Cape Cod to Greenland, and circumpolar. 

 Northern Europe, Behring's Straits, Japan. 



{h) In Acadia; — (in N. B.) Grand Manan, twenty to forty 

 fathoms, mud, Stimpson. Rather abundant in sheltered 

 places, also found in Friar's Cove. (In N. S.) iVnnapolis 

 Basin, rare, Verkruzen. Halifax Harbor, Willis and Jones. 

 Not reported from Prince Edward Island nor southern part 

 of the Gulf. Probably occurs in mud and fine sand in many 

 places in the Bay of Fundy and on the Atlantic coast of Nova 

 Scotia. 



Habits. This is a very well-marked species, and, except in its- 

 young stages, cannot be confounded with any other on our coast. The 

 valves are of a rounded form, and very convex or much hollowed out. 

 On each, radiating fandike from near the hinge, are about thirty-six 

 raised angular ribs, which, on the free edge, give the shell a scalloped 

 or crenulated appearance. The epidermis frequently rises into a bristly 

 fringe on their summits, especially in young specimens, and this, with- 



