GASTEROPODA. 321 



T. Montagui, Gray. 

 Portmarnock, Mr. Warren. In or near Bantry Bay, Mr. M 'An- 

 drew. 



T. striatus, Mont. 



Professor Allman di-edged about a dozen in one haul, from about 6 

 fathoms, in Baltimore Harbour. Cork and Bantry, Mr. Humphreys. 



T. exiffuiis, 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. 

 31. crassa, Brown. 



This littoral species, found on rocks, stones, &c., is unknown to me 

 further North on the eastern line of coast than Ballywalter, 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 1847, Mr. Warren gave me siiecimens from 

 Bundoran. 



Genus Margarita. 



M. coiumtim's, 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. suhcarinatus, Turt. 



Noticed under the name of Trochus rugosus by Brown (Wern. Mem. 

 vol. ii. p. 520, pi. 24, f. 5), as " found in di'ifted 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 Iantiiina. 

 /. 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 eq.uinox ; 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 



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