XXli MOLLUSCA OF SOMERSET. 
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= ui 6 |= 
Se Se eos oe | eee 
s|/a/e|/= el |e | ea aa ee 
> > 3 < o = oa ” @ | 
= = S S = + + xD | 
SSIS ISIE EE 
S/S/9/al/a/ol/Pz/ZIS 
. . = Ss r r 
Unio tumidus Me ee wef-1-{-|-| |X| x]-|x 
Anodonta eygnea wie PP lah e-file) ) iol. | 
Spherium rivicola son By ae a et bead (Ea P= Gio I>. [> 
S. corneum ape ss wae | he HO Te | XR ONE ox axe ox 
S. lacustre oe ve wae =i | ela TK | RG Se exe ee 
S. pallidum cae ses wl-|-|-|- —|-]|- 
] 
Pisidium amnicum sae --(—/|-—|x}-|—|X]/|x]x 
P. henslowianum ... ict w(-|—-l-]-]|-|X|x )x}] / 
P. subtruncatum ... sve aoe HK || SealP eC || NT NU axel toc toe 
P. pulchellum __... si --[-|—|}x}—-|-|X]/]/ |x 
P. pusillum ee ss oe 8] | |) Ree I | NG ae 
P. nitidum aa Be we(—|—|x]—|X|X] /}-]x 
P. obtusale sa ese fee fees pues | mails! hh ff 
P. gassiesianum (=roseum) BOE uke elle S potie< ches oelea ec 
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the west of Ireland, and the south-west of England and Wales. 
Dr. Scharff considering discontinuous distribution to be an 
index of antiquity, assigns our terrestrial mollusca to two 
provinces : 
(1) England and Wales (except south-west). 
(2) South-west England and Wales, and the whole of 
Scotland and Ireland. 
The second province contains six species which are entirely 
absent from the first, viz.: Testacella mangei Feérussac, 
Geomalacus maculosus Allman, Helicella barbara  Linné, 
Hygromia revelata Férussac, Helix pisana Miller, and Jaminia 
anglica Férussac. 
Three, viz.: T'estacella maugei, Helicella barbara (= Helix 
acuta), and Jaminia anglica (= Pupa ringens) occur in Somer- 
