of the North of Ireland. 59 



Where practicable, I have preferred giving verbatim quotations from the 

 authors quoted, in place of a general summary of their remarks. 



Of the 404 British species contained in that portion of the Sub-Kingdom 

 Mollusca, as described by Jeffreys, to which the present paper refers (i.e. the 

 classes Brachiopoda, Conchifera, Solenoconchia, and Gasteropoda to the end of 

 Pleurobranchiata), our district has yielded 291, or very nearly f— 1 1 9 bivalves 

 and 172 univalves — exclusive of such species as are importations or fossils, and 

 which are printed inside brackets. On the whole, the Fauna has a northern 

 aspect, since, of these 291 species, 36 are boreal forms, which live either not at all, 

 or very sparingly, south of Britain, while only 12 are essentially southern, having 

 been taken seldom or never north of the British coasts ; the remaining 243 inhabit 

 seas both north and south of our islands. As is to be expected from geographical 

 considerations, the southern species frequent chiefly the western shores of the 

 province, while the northern forms have been mostly taken on the eastern coast. 

 Of the northern types, Crenella decussata, Leda minuta, Tectura testudinalis, 

 Emarginula crassa, Trichotropsis borealis, and Trophon truncatus, will serve as 

 examples — they have all been taken alive in our waters ; while the following 

 will serve as representatives of the southern forms which the district yields — 

 Modiolaria costulata, Crenella rhombea, Area lactea, Troehus Duminyi, Natica 

 sordida, Ovula patula. 



Only one species is, as a British shell, confined to our province— Troehus 

 Duminyi ; it occurs on the western coast, and is a southern shell, its foreign 

 stations being all Mediterranean. 



The Testacea of the counties of Antrim and Down may be considered as 

 pretty well worked up, though the North of Antrim offers a good field that has 

 been scarcely touched. County Londonderry contains extensive sandy beaches, 

 which yield a large variety of species, that of Magilligan especially ; here the 

 observations have been chiefly made from shore, and dredgings in the deeper 

 water might yield interesting results. I find no record whatever of any dredging 

 in Lough Foyle. From the extensive coast-line of County Donegal, with its 

 magnificent headlands and deep inlets and sandy bays, comes hardly a single 

 note to enrich the list which follows. At Bundoran, indeed, in the extreme 

 southwestern corner of the county, Mrs. Hancock made many finds, which she 

 communicated to Thompson ; and here Mr. "Waller discovered a new British 

 Troehus, T. Duminyi, whose only British station is still Bundoran ; but beyond 

 these, the conchology of the most northern county of Ireland still remains to be 

 investigated, and will probably amply repay the investigator. 



Mr. Thompson appears to have placed but light value on the condition 

 (hiving or dead) of the shells which he found in his dredgings, or thrown up 

 by the tide, and in many instances does not mention this point at all. In the 

 present paper the writer perhaps has erred in the opposite extreme, and has 

 placed undue importance on this point, but it does appear to him to be of 

 interest and importance to know whether or not a shell has been taken living in 

 the district. It is to be remembered, however, that the fact of a species not 

 having been found living, is by no means positive proof that it no longer 



