18 INTRODUCTION. 
indigenous species. | Physa acuta (at Kew Gardens and Glasgow), 
flelix villosa (Cardiff), Hf. ¢errestris (Dover), Aulimus goodallit 
(Bristol), and Clauszlia parvula (Stourbridge), all of which have been 
introduced recently and have been found alive, have not been accorded 
this privilege. A few dead specimens of Pepa cinerea have been 
found near Stonyhurst, but this southern form has probably been 
received from abroad by some member of the Jesuit College and 
turned out purposely or not as may be. 
SPECIES OF DOUBTFUL ORIGIN. 
Dretssensia polymorpha, first noted in 1824, is supposed to have 
come in ballast. Mr. B. B. Woodward, however, mentions as remark- 
able the finding of a single valve in the alluvial deposit of the London 
district.* Spherium pallidum is also suspected of being a foreign 
importation. Mr. Woodward, in the same paper, says ‘* Hel¢x pomatia 
and A. asfersa are not found anywhere [in Britain] in pre-Roman 
deposits, though frequently found with Roman remains. They were 
probably introduced about that time. . . . WH. cantiana was 
probably introduced after this time.” 
INDIGENOUS SPECIES RECENTLY NOTICED. 
Testacella mauget, Helix pisana, and FH. obvoluta were formerly 
under the bann of suspicion, but are now recognised as indigenous. 
Limax cinereo-niger, Hyalinia luceda, and Vertigo moulinszana, 
though they have escaped notice until quite recently, can hardly have 
been introduced from abroad, and may fairly claim to be included in 
the British list. 
Hyalinia glabra (now called helvetica), noticed and figured by 
Turton in 1840 and brought to notice by Mr. T. Rogers in 1870, has 
an undoubted claim to rank as British. 
The plate on the opposite page is intended to illustrate the terms 
for the different parts of shells and slugs. 
Ae RMON ne ee ee 
* Proc. ‘‘ Geologists’ Magazine,” Aug., 1890. 
