COOKE: DISTRIBUTION OF PUBPUSA LAPILLUS. 201 



Museum of Natural History, Leiden. The shell is fairly solid, well 

 developed, not dwarfed; length 1-25 inch, breadth -75; mouth *75 

 long (to front end of canal), shape long oval; canal broad, well 

 marked; outer lip simple, not denticled ; sculpture, a number of 

 strong transverse cords or blunt ridges, about eleven on the body- 

 whorl, suddenly ceasing, to form a sort of shoulder, some way below 

 the suture ; colour dirty white. 



The British Museum has three specimens, dated 23rd June, 1843, 

 labelled "Greenland", purchased from Dr. MoUer, and with a label 

 attached in bis handwriting. The shell is solid, strongly corded, 

 spire prolonged, aperture orange-coloured, outer lip simple, scarcely 

 thickened, specimens heavier and more solid than the Leiden shells. 

 They closely resemble specimens from various parts of Scotland. 



Considerable uncertainty appears to prevail with regard to the 

 extreme northern range of P. lapillus on the east coast of North 

 America. It is certainly not found in Northern Labrador; it does not 

 occur in a list of Mollusca from Ungava Bay and the adjacent Arctic 

 seas (Dall 21). Hancock (42) did not find it on the west coast of 

 Davis Strait. A catalogue of Mollusca dredged on the Labrador coast 

 in 1882 (Bush 13) does not contain it, though such common species 

 as Littorina rndi's, Mat., and Z. littorea, L., are included. The coast 

 referred to lies between N. lat. 52° 48' and 51° 33', and thus includes 

 part of the Gulf of St. Lawrence. Nor does it occur in a list by 

 Packard (94) of shells obtained while coasting from Little Meccatura 

 Island, in the Gulf of St. Lawrence, to Hopedale (in N. lat. 55° 25' on 

 the East Labrador coast), and the same author (Packard 93), publishing 

 a list of dredgings, etc., near Caribou Island, at the entrance of the 

 Straits of Belle Isle, remarks that the "entire absence of any 

 specimens of Purpura lapilhis was inexplicable, though I searched for 

 that shell". In the more sheltered waters of the western portion of 

 the Gulf of St. Lawrence, P. lapillus occurs e.g. at Gaspe, in New 

 Brunswick, on stones near the shore (Dawson 28), "on the whole 

 coast below Little Metis, extremely common " (Bell 10), and at 

 Anticosti, not very common (Packard 93), while Whiteaves (125) 

 gives it in his list of marine Mollusca of East Canada, no doubt from 

 this part of the gulf. It would thus appear that the whole of the 

 East Labrador coast, and even the Canadian shores for some distance 

 within the Straits of Belle Isle, offer no habitat for this species. 



Verkriizen (121) records a var. ponderosa from Notre Dame Bay in 

 North Newfoundland (N. lat. 50°). If this approximates to the most 

 northern point of its occurrence on the east coast of America, no 

 better illustration could be afforded of the power of very cold water 

 to bar back a species, for on the other side of the Atlantic the 

 latitude of 50° just touches the Lizard. Accordingly Gould's (40) 

 statement that P. lapillus "occurs on rocks everywhere from Green- 

 land all through New England" will need some modification. 



P. lapillus is extremely abundant on the northern coasts of Nova 

 Scotia (Jones 56); at Grand Manan, New Brunswick, a large 

 chocolate-coloured form occurs (Dr. Gratacap). Verkriizen (120) 

 records it from Annapolis, and Nova Scotia in general. On the coasts 



