116 THE ECONOMIC MOLLUSCA OF ACADIA. 



species, and is nearlj^ as broad as long. It is about half an inch id 

 diameter. 



Economics. Probably similar to Xylophaga dorsaUs. 



30. Xylophaga dorsalis (Turton) Forbes and Hanley. 



[Xylophaga, wood-eating ; dorsalis, from plates on its back.] 



[The Teredo dilatata of Mr. Whiteaves' first report, as he 

 tells us in his second.] 



Distribution, (a) General; — Northern Atlantic ocean. 



(b) In Acadia; — New Brunswick and Nova Scotia waters. 



Mr. Whiteaves says in his first Report, — "Principal 

 Dawson informs me that great damages have already been 

 done to the woodwork of wharves and harbors in Nova Scotia 

 and New Brunswick, by this species of Teredo. 



Habits Though in general structure, habits, etc., it is probably 

 quite like Teredo tmvalh, it differs much in appearance. It is from one 

 inch to one and a half inches long and has the organs more concentrated 

 than in Teredo, forming a spherical mass from which a slender tube 

 projects backward bearing tlie siphons. We find it showing characters 

 intermediate between the Teredos and the genus Pholas\ the latter are 

 shelled h'valves which bore into stone. This species would hardly be 

 distinguished by the beginner from the last. 



Economics. On account of its smaller size, and conse- 

 quently short burrows, it is not so destructive aa the larger 

 Teredos, but it nevertheless does much damage both to floating 

 and fixed timber works in Europe. 



Mr. Whiteaves says in his first Report, — "Mr. Nelson 

 Davis, of Montreal, tells me that the brigantine ' Magdala,^ 

 which was built at St. John, N. B., was completely riddled 

 by this ship-worm some time ago, on her first voyage from 



St. John to Liverpool The whole of the ship's 



bottom had to be renewed and covered with copper sheeting 

 before she was again seaworthy." 



