Nichols — A List of the Marine MoIIusca of Ireland. 479 



In this list those species that have only been procured in the 

 deep -^ater district are included in square brackets, and can thus be 

 easily distinguished. 



The more important varieties are included, but their distribution is 

 not by any means satisfactorily known, as they have only occasionally 

 been recorded. 



The Mollusca obtained at Baltimore, September, 1895, and at 

 Dungarvan, October, 1896, by Professor Johnson and myself , for the 

 Fauna and Elora Committee of the Eoyal Irish Academy, are included 

 in this list ; also the Mollusca that were dredged in the Hoyal Dublin 

 Society Fishiug Survey, 1890, 1891, and which were determined by 

 Mr. H. K. Jordan. Otina otis, Alexia denticulata, MdamfUB liden- 

 tatus, and the species of Paludestrina {Hydrohici) were included by 

 Dr. ScharS in "The Irish Land and Freshwater Mollusca," in Irish 

 Naturalist, i., 1892, and are not repeated in this list. I have also 

 omitted a large number of species of Mollusca which have at various 

 times been recorded as Irish, but have been wrongly determined, im- 

 ported in ballast or otherwise, or have only been found in a fossil state. 



The arrangement of the families and genera follows closely that 

 adopted by Cooke in "The Cambridge INatural History," iii., 1895. 

 As regards nomenclature, papers by Chaster, Melvill, Monterosato, 

 iN'ewton, I^orman, Smith, &c., have been consulted, but whenever the 

 name in this list differs from that employed by Jeffreys in "British 

 Conchology," I have also given Jeffreys' name. 



The general distribution of each species is given briefly, and has 

 been principally derived from Jeffreys' "British Conchology" and 

 his other writings ; the "Challenger" Eeports, the works of Cams, 

 Dall, Kobelt, Locard, Monterosato, JSTorman, Sars, YerriD, AYatson, 

 &c., have also been referred to. 



My best thanks are due to Mr. James Thompson, of Belfast, for 

 the loan of the late Mr. "W. Thompson's Manuscript for the 

 4th volume of the " ISTatural History of Ireland": to Mr. B. L. 

 Praeger for allowing me to consult his notes on the Mollusca of the 

 JSTorth of Ireland : to Professor D'Arcy W. Thompson for a list of 

 Mollusca obtained at Boundstone : and to Mr. G. P. Parran for a list 

 of Mollusca collected at ]S'arin Strand, county Donegal. The species 

 in both these lists were determined by Dr. G-. TV. Chaster. I am also 

 indebted to Dr. Chaster and Mr. J. T. Marshall for assistance in deter- 

 mining some critical species. 



Excluding some very doubtful Irish species, the number of species 

 of marine Mollusca recorded in Thompson's "Natural History of 



2 51 2 



