GASTEROPODA. 
321 
T. Montagui , Gray. 
Portmarnock, Mr. Warren. In or near Bantry Bay, Mr. M ‘An- 
drew. 
T. striatus, Mont. 
Professor Allman dredged about a dozen in one haul, from about 6 
fathoms, in Baltimore Harbour. Cork and Bantry, Mr. Humphreys. 
T. exiguus, Pult. 
I have seen two specimens in Mr. Warren’s collection, they were given 
to him as from Wicklow coast, but he is not certain of the truth of the 
statement. 
Genus Monodonta. 
M. crassa, Brown. 
This littoral species, found on rocks, stones, &c., is unknown to me 
further North on the eastern line of coast than Bally waiter, County Down 
(54^° lat.). Southward it is common, but does not appear to be universally 
distributed. At the South Islands of Arran and Roundstone I have pro- 
cured it in abundance; in 1S47, Mr. Warren gave me specimens from 
Bundoran. 
Genus Margarita. 
M. communis, Mont. 
Turton notices this species in his catalogue, merely as from drifted sand. 
Portmarnock, Mr. Warren has it thence. It inhabits the Laminarian 
region of the Loughs of Larne, Belfast, and Strangford, being found on 
the broad living fronds of the Laminaria digitata, &c., brought up by the 
dredge. 
Genus Adeorbis. 
A. subcarinatus , Turt. 
Noticed under the name of Trochus rugosus by Brown (Wern. Mem. 
vol. ii. p. 520, pi. 24, f. 5), as “ found in drifted sand at Portmarnock, 
by Dr. Turton, who says it is not uncommon.” Found in fine shell-sand. 
In shell-sand, Belfast Bay, Mr. Hyndman. 
Genus Scissurella. 
S. crispata, Flem. 
Mouth of Belfast Bay, 27 fathoms, two dead specimens dredged by 
Mr. Hyndman. 
Genus Ianthina. 
I. communis, Brown. 
This interesting oceanic species is not uncommon at the more genial 
periods of the year, but chiefly in autumn ; not unfrequently about the time 
of the equinox ; borne in a living state on the waters of the ocean, to the 
shores of Ireland, from the Giant’s Causeway, westward along the whole 
line of coast to Cape Clear. Beyond these limits it is more rare ; only in 
one year (1836) am I aware of its occurrence so far southward, on the 
East coast, as the County of Down, from Bangor to Donaghadee ; on 
the 11th of August, that year, a very few specimens (some containing the 
