346 MOLLUSCA. 



the doubt about the species) by Prof. Harvey. The Bays of Mayo and 

 Gahvay are its chief abode. 



By Major M'lh'oy of Westport I was, in 1840, favoured with a spe- 

 cimen from Clew Bay ; about the same time it was dredged in Killery 

 Bay, from about 8 to 12 fathoms on oozy ground. In Birterbuy Bay it 

 Avas procured in some quantity and very large, by Dr. Farran. With re- 

 spect to Clifden Bay, Mr. Barlee remarked in a letter to me dated Sept., 

 1845, that he found no shells abundant there but Turritella terchra, Lvcina 

 spin if era, and Amphidcsma Boj/sii. Mr. M 'Andrew dredged it in or about 

 Bantry Bay. At Red Bay, Co. Antrim, I found a valve of this species ; 

 one was brought up during Capt. Beechy's dredging off the Mull of Gal- 

 loway, on the coast of Scotland, depth 145 fathoms. 



L.Jfexuosa, Mont. 

 Dublin coast, Br. Turt. Widely distributed, but in sparing numbers. 

 Dredged in Strangford Lough from 15 to 20 fathoms, muddy bottom, 1846 ; 

 previously obtained there from about half that depth, and on sand, Mr. 

 Hyndman and W. T. Dredged off Bundoran, and in Clew and Killery 

 Bays, in 1840. 



Genus Amphidesma. 

 A. 2»'ismatica, Laskey. 

 This species, although found on each side of the island, is by no means 

 generally distributed. I have found it thrown ashore on the sandy beach 

 of Magilligan and Belfast Bay ; in which latter it has been ckedged from 

 20 fathoms (sandy ground) by Mr. Hyndman ; who likewise brought it 

 up from 50 fathoms off the South Rock, Co. Down. 



A. JBoijsii, Turt. 

 Dublin coast, Turt. Br. The most generally distributed species of this 

 genus. Dredged in Belfast Bay and Strangford Lough sparingly, from 

 oozy sand, at a depth of about 8 — 10 fathoms. Dundalk Bay, Mr. Hynd- 

 man. Dublin coast. Miss M. Ball. Dr. Farran has favoured me with 

 very fine sjiecimens from the stomach of sole taken on the Dublin coast. 

 Dredged in Clew, Clifden, and Killery Bays, in limited numbers, 1840. 



A. tenuis, Turt. 



I have received specimens of this well-mai"ked species from Larne 

 Lough, County of Antrim. Dr. Farran includes this in his list of Bir- 

 terbuy Bay shells, and Mr. Warren writes to me (Feb. 1847) that he has 

 obtained it at Portmarnock. 



Amphidesma intermedia, Thompson. 



Shell oval — oblong, nearly equilateral, white with prismatic colours. 



Length 2J lines ; breadth 4 ; thickness 1^^ ; beaks almost central ; shell 

 nearly equilateral, rounded at each end, more particularly at the poste- 

 rior ; thin, semi-transparent, glossy, white with prismatic hues. This spe- 

 cies is intermediate in form or outline between Amph. prismatica and 

 A. Boi/sii, and also in general characters, but on the whole may perhaps 

 be said to approximate the latter more nearly ; its form, however, at once 

 marks it as distinct from A. Boi/sii, than which it has the beaks more 

 central, is broader and more equilateral, has the apex rather more marked 

 and pointed, and is beautifully iridescent inside and outside ; the teeth 

 do not present any marked differential characters. 



