346 
MOLLUSCA. 
the doubt about the species) by Prof. Harvey. The Bays of Mayo and 
Galway are its chief abode. 
By Major MTlroy 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 
was 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 terebra , Lucina 
spinifera, and Amphidesma Boysii. 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.Jlexuosa, 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. prismatica, 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 dredged from 
20 fathoms (sandy ground) by Mr. Hyndman ; who likewise brought it 
up from 50 fathoms off the South Rock, Co. Down. 
A. Boysii , 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 specimens 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 Avell-marked 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 2f 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. Boysii , 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. Boysii, 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. 
