6 4 Praeger—The Marine Shells 



size, and all P. ingens or P. fragilis (Turt. Brit. Biv.)," and he gives Port- 

 rush, Belfast Bay, and 50 fathoms off Island Magee, as localities where 

 examples have been procured. It has been found at the first-mentioned 

 station by Miss Richardson also. Probably the earliest record of this shell 

 in our district is that in a letter from the Rev. Robert Innes, Rector of Magil- 

 ligan, to Dr. Nicholson, Bishop of Deny, dated June 2nd, 1725, in which he 

 describes a large example found in that neighbourhood. General Portlock, of 

 the Geological Survey, writing in 1843*, and commenting on the above, says 

 " this coast continues a good locality for Pinna fragilis ; to obtain the fish in 

 the valves they must be dredged up from deep water." 



Ittytllus edulis, Linne. 



Common on all our shores. Thompson gives some interesting notes as to 

 the rapid growth and increase of this prolific species ; for instance, that on a 

 buoy in Belfast Lough, cleaned after being 5 years down, "the entire cir- 

 cumference of the base, for a foot of space always under water, was covered 

 a foot thick with full-grown mussels " ; and that the bottom of the pilot-boat 

 after its being 9 months afloat, yielded quantities of mussels 1£ inches long. 



var. incurvata. "The only bivalve seen on Tory Island, where it is abun- 

 dant, covering the rocks" — Thompson. 



var. pellucida. "Common in some parts of Belfast Bay" — Thompson (sub 

 M.pellucidus). Cultra, S. A. Stewart— Belf. Mus. Coll. 



Xttytilus modiolus, Linne. 



The " horse-mussel " is common, living in gravelly and muddy localities in 

 6-90 fathoms. Dickie found it very abundant in Strangford Lough (4-25 

 fathoms), coming up in quantity in almost every haul of. the dredge (sub 

 Modiola modiolus). 



var. ovata. "County Antrim (J.G.J.)" — Jeffreys. 



IMCytllus Adriaticus, Lamarck. 



Rare in the province. Thompson mentions it (sub Modiola tulipa) from 

 Belfast Lough ; and Hyndman, under the same name, as living sparingly in 

 10 to 20 fathoms, while he obtained dead valves on the Turbot Bank, and 

 in 75 fathoms near the Maidens. Strangford Lough— Belf . Mus. Coll. I have 

 found complete and fresh-looking specimens on the shores of Belfast and Car- 

 lingford Loughs. 



Mytilus paaseolinus, Philippi. 



Living in 15-20 fathoms off Belfast Lough, and in 70-90 fathoms off Larne 

 — Hyndman (sub Modiola phaseolina) ; and in 4-20 fathoms in Strangford 

 Lough — Dickie. 



XMCodiolaria marmorata, Forbes. 



Found in numbers, embedded in the skin of Ascidia mcntula and other 

 Tunicata, all round the coast, in depths up to 90 fathoms. Hyndman places 

 it under genus Crenella, and Thompson and Dickie under Modiola. 

 * Eeport on the Geology of the County of Londonderry <fcc., p. 23. 



