10 HYGROMIA STRIOLATA. 
Variation.—The variation in //. striolata 1s somewhat perplexing 
owing to its intergrading with /7. hispida and other closely-allied forms 
and such intermediate links have in many cases been proposed as distinct 
species. Dr. Westerlund accepted three British species: //. striolata, 
H. rufescens, and H. abludens. 
The Helix abludens Locard, recorded hitherto only from Dublin, Jersey, 
and Boulogne, and which Dr. Scharff found commonly in his garden at 
Leeson Park, Dublin, and regarded as a flattened form of //. striolata 
perhaps produced by unhealthy animals. 
A large and thick-shelled form from the alluvium of the Danube is 
recognized by Herr Clessin under the name of var. ad/uvians, but I know 
of no other description. 
In the North-east of Ireland, where it is local and rare, it is said by 
Irish conchologists to merge almost insensibly into //. hispida, which is 
quite a common species there. 
‘The Rev. Canon Norman has observed that in shady umbrageous places 
the shells are usually large and horn coloured, while in drier places the 
shells are smaller, deeper in colour, and with a more elevated spire. 
A study of the characters of the shell from the earliest stages would 
seem to indicate that this species is probably in process of quitting the 
more shady sheltered and moist stations amongst which—judging by its 
hirsute juvenile stage—its immediate ancestors lived, and is now gradually 
assuming the occupancy of more open and drier ground, its food and 
habits probably not directly conflicting with those of the more dominant 
true Helices. 
This change of habit is indicated and attested by the attenuation of the 
epidermis, the usually total loss of the epidermal hairs in the adult stage, 
and the greater development of the calcareous basis of the shell. 
The white and more calcified peripheral zone is most distinctly and 
most frequently shown towards the limits of its geographical range, thus 
implying it to be an ancient characteristic, which is probably on the road 
to extinction. 
The var. c/essin?, in which the hairy investment persists to adult life, 
shows that the life of this form is still spent within the leafy shades, as in 
such situations the thicker epidermis and epidermal outgrowths are deve- 
loped and fostered. 
‘I'he undescribed varieties cornea and subcornea of Bouchard-Chantereaux 
appear to be but very slight subvariations of the typical shells. 
VARIATIONS OF FORM OF SHELL. 
Var. danubialis Clessin. 
Helix danubialis Clessin, Jahrb. Deutsh. Mal. Ges., 1874, p. 184, pl. 8. 
Irrutictcola rufescens var. montana Clessin, Deutsche Exc. Moll., 1884, p. 158. 
SHELL more compact and with a more elevated spire. Diam., 10-11°5 mill. ; 
alt., 6:5-7 mill. 
The sub-var. montana seems to differ only in its usually darker colour. 
This variety, which is perhaps the mountain variety men- 
tioned by Reeve, is practically synonymous with the Helix 
montana Clessin, etc., is a noticeably tall and compact shell, 
which Clessin describes as brown, translucent, and finely striate, 
with a slightly angled and paler periphery. Clessin’s illustrative Fic. 22.— Helix 
1 ‘ej atisfactorv 1s ; AE : . danudb sialis Clessin 
figure is not satisfactory. Diam., 11 mill. ; alt., 64 mill. ed (alter Clee 
ENGLAND. 
York S.W.—Bretton West, Barnsley, April 1910! W. E. Brady. 
York Mid W.—One specimen with a remarkably raised spire found at Skipton 
by Dr. R. F. Scharff, which may be probably allocated here. 
