198 Mr. W. Thompson's Catalogue of the Land and 



(county Waterford), it is stated by Mr. R. Ball to be found 1 . The 

 form to which M. Michaud has applied the name of Unio Roissyi is 

 common to several localities in Ireland. 



The following Catalogue at the same time exhibits the number of 

 British species which Ireland possesses, and according to the pre- 

 sent state of our information, those likewise in which the country 

 is deficient. In the Table, the columns headed " elsewhere in 

 north," &c. are used only with reference to species not enumerated 

 in the preceding column or columns, and to show that geogra- 

 phical position is not the cause of absence ; thus, for instance, 

 Helix virgata is not found about Belfast, but occurs in the north 

 of the county of Antrim. The genera Arion and Limax were al- 

 together omitted in most of the Catalogues supplied me. The 

 Catalogue for Belfast 2 is on my own authority : Dublin, various ; 

 Limerick and Miltown Malbay, William Henry Harvey, Esq. ; 

 Cork, Mr. John Humphreys (1834) and the Rev. Thomas Hincks 

 (1840) — the species added by the latter gentleman are marked 

 thusf; Youghal (county Cork), Miss Mary Ball; La Bergerie near 

 Portarlington (Queen's county), Rev. Benjamin J. Clarke; Fin- 

 noe near Burrisakane (Tipperary), Edward Waller, Esq. 3 



1 Unio pictorum is noticed by Dr. Turton, in his ' Catalogue of Irish 

 Shells/ as found in " rivers about Cork/' The species is not known as na- 

 tive to my correspondents in the south, and I am disposed to believe was er- 

 roneously inserted in the catalogue. 



2 All the species marked with an asterisk in the column headed " Bel- 

 fast" have been obtained within four miles of the town. 



3 The prevailing geological features of the neighbourhood of Belfast are 

 trap, chalk, greensand formation, variegated marl formation and grauwacke ; 

 of Dublin, mountain and calp limestone, granite and quartz-rock ; of Li- 

 merick, Cork, and Youghal, " limestone and old red sandstone" (Griffith) ; 

 of Miltown Malbay, " coal-shale and sandstone" (Griffith) ; of La Bergerie 

 and Finnoe, mountain limestone. 



