100 DEPARTMENT OF THE NAVAL SERVICE 



8 GEORGE V, A. 1918 



It is interesting to note that one of the molluscs which is common in Sydney 

 harbour, Cape Breton island, where Teredo has perhaps its maximum abundance, 

 IS the rock borer Zirfaea crispata. Although reported rarely in the gulf of St. Law- 

 rence by Whiteaves I have found it rather abundant near low-tide mark at North 

 Sydney. Along the Bay of Fundy coast of Nova Scotia, however, I have found no 

 trace of it. Stimpson reports it to be very rare at Grand Manan. Verrill has 

 recorded it at from 8 to 70 fathoms in the Bay of Fundy. But it does not appear to 

 occur in the Bay of Fundy near tide mark, as it does at Sydney. Like Teredo, 

 Z. crispata appears to be absent or rare along the Atlantic coast south of the Bay of 

 Fundy. This species, like T. navalis, has a wide distribution. On the Pacific coast 

 it is reported from VancouA'-er to San Diego, California, by Carpenter.^ It is dis- 

 tributed along the European side of the Atlantic from France to northern Norway.^ 

 Although found in an elevated beach near Christian shoal, Greenland, Jensen states 

 "that Zirfaea (Pholas) crispata no longer lives at Greenland may be regarded as a 

 fact." ^ 



Another boring shell which is associated with T. navalis around the shores of 

 Prince Edward Island is Petricola pholadlformis. The Canadian Geological Survey 

 Museum collections include a specimen of hard red shale with shells of this mollusc 

 from Charlottetown, P.E.I. Concerning this shell. Dr. A. G. Huntsman* writes: 

 ^' Petricola pholadiformis is abundant in the lower part of the gulf of St. Lawrence 

 around Prince Edward Island, and occurs boring in the red sandstone there. It 

 has been reported by Verkruzen from St. Marys bay, Nova Scotia, and I have myself 

 dredged it there in .'^0 fathoms hard clay bottom. I have not found it in the Bay 

 of Fundy proper." Dr. Huntsman's observations on this shell indicates pretty clearly 

 the discontinuous distribution of T. navalis and Z. crispata, which eliminates them 

 from the fauna of the upper part of the Bay of Fundy. 



Teredo navalis belongs in the gulf of St. Lawrence to an isolated faunal group 

 which is confined to Dawson's warm " Acadian bay." The subboreal or syrtensian 

 fauna of the central and northern part of the gulf of St. Lawrence are excluded from 

 this fauna. Concerning this fauna, Dawson^ wrote : " It thus forms a peculiar and 

 exceptional zoological province " . . . "It affords to the more delicate marine 

 animals a more congenial habitat than they can find in the Bay of Fundy or even on 

 the coast of Maine." 



Among the characteristic species which comprise this Northumberland strait 

 colony of the Acadian fauna are the following: — 



Ostrea virghiica. 

 Venus mercenaria. 

 Zirfaea crispata. 

 Astarte undata. 

 Crepidula fornicata. 

 Crepidida plana. 

 Ilyanassa ohsoleta. 



Some of these species, as 0. virginica and V. mercenaria are entirely absent from 

 the Bay of Fundy waters. Some others, like /. ohsoleta are entirely absent on the 

 west coast of the Bay of Fundy but present in the warm shallow inlets on the eastern 

 side of the bay. The Northumberland Strait colony is separated from the northeastern 

 border of the New England zone of the Acadian fauna by the deep basin of 

 the Bay of Fundy and the Atlantic coast waters of northern Nova Scotia. The 



1 Dall considers the Pacific Coast form to be a species distinct from Z. crispata. 



2 Adolf S. Jensen, Middelelser on Greenland, Vol. XXIX, 1905, p. 296. 



3 Ibid. 



* Letter to the author, February 12, 1917. 



5 Dawson, J. Annual address. Can. Nat. Ser. 2. Vol. VII, 1S75, p. 277-8. 



