JACKSON : THE CANDIDULA SECTION OF HELICELLA. I95 



IMollusca paper^ and Clare Island Report,- and distinguishes two 

 forms — one, which he calls the large western form, found in the west 

 and north-west of Ireland, and the other, a smaller form, from the 

 central limestone plain. This latter form he considers to be more 

 akin to that found on the chalk downs of the south of England, and 

 referable to Montagu's H. caperata. This would also appear to be 

 the H. striata of Draparnaud (in part). 



In a footnote on p. 24 of his Clare Island Report he admits that 

 " the synonymy of this group of shells has been so muddled that it is 

 now quite impossible to be certain of the identity of Poiret's species. 

 This has led to the adoption of Montagu's name by many authorities." 



Since so much confusion exists regarding Poiret's intersecta no 

 useful purpose is served by adopting the name and it is preferable to 

 adhere to H. caperata Mont. 



The large ' western ' form is not restricted to Irish localities, as it 

 occurs with the smaller form at several places in this country. 



H. caperata is widely distributed in the British Isles ; it has been 

 recorded from the Channel Isles, Isle of Man, Wales (10 vice- 

 counties), England (52 vice-counties), Scotland (19 vice-counties), 

 Ireland (33 vice-counties). 



On the continent it is also widely diffused and ranges through 

 France and Germany, Spain, Portugal, and Italy, to N. Africa 

 (Algeria), mainly as H. intersecta. It is said to occur also in Greece 

 and Palestine. It appears to be distinctly of western European 

 distribution, and has not been found in North Europe. 



There are some eight or nine well-known varieties in this country, 

 of which the most familiar are ornata z.x\6.fuiva. 



Some excellent notes on the variation of this species are given by 

 the Rev. S. Spencer Pearce in the pages o^ i\\\?, /ojimalf' 



Its fossil distribution has been investigated in the South of England 

 by Messrs. Kennard and Woodward, who record it from numerous 

 Holocene and Pleistocene deposits.^ On the continent it has also 

 been recorded by Locard and others as fossil at several places and 

 horizons. 



Helicella gigaxii (Charp. MS.) Pfr. — For many years this 

 species had been looked upon, and recorded as, a variety of U. 

 caperata, notwithstanding the fact that it presents such striking 

 characters, and had been considered as a good species by reliable 

 continental authorities. 



1 Proc. Roy. Irish Acad., vol. 29, 191 1. 



2 Op. cit. vol. 31, igi2. 



3 Jovrn. of Conch., vi., iSSg, p. 123, ei seq. 



4 Note. — There is a possibility that all tliese records do not apply to H. caperata but 

 include also,^r belong entirely to, the following species, H. gigaxii. 



