HWELIX HORTENSILS. Bit 
Variation.—The variation of //. hortensis is chiefly in the colour or 
shade of the general tint of the shell, which may vary from almost pure 
white to a very dark greenish-black ; the size, substance, and shape of the 
shell are also subject to certain differences, while variations in the number 
and arrangement of the spiral bands are very few, the great bulk of the 
specimens possessing all the five normal bands or being entirely baudless. 
Like its allies, the ground colour of the shell of /Telix hortensis is chiefly 
due to the periostracum or epidermis, while the spiral zonulation or 
banding is seated in the calcareous layer beneath, but unlike /7. nemoralis, 
the broken-banded variation, known as var. punctella, so common under 
certain conditions in that species, is in //. hortensis very rarely found. 
Herr Clessin has remarked that the most brightly coloured shells are 
most frequent in open-wooded grounds, while the duller specimens with 
delicate and somewhat deciduous epidermis are met with about old ruins 
and on isolated shrubs, chiefly of Prunus spinosa, and the dark-coloured 
varieties are almost restricted to dense deciduous woods with a thick 
carpet of vegetable débris. 
The umbilical region of the shell is sometimes noticeably darker in this 
as in the preceding species, and Dr. J. W. Williams suggested that this 
darkening was due to discolouration caused by the constant damp to which 
the base of the shell is exposed, but it may possibly be atavic in character, 
comparable to the whitish opacity so conspicuous beneath the shells of 
certain of the Hyaliniw, as previously suggested. 
In America, according to Dr. Dall, the more brightly-colonred types with 
sharply-defined bands form an insignificant proportion, while the shells on 
the whole are smaller than the average of European shells. 
The colour of the lip is very variable, and though usually white, may 
be of almost any intermediate shade between pure white and deep black, 
but it is noteworthy and a probable testimony of the more recent acquire- 
ment of the pigmented lip that the darker shades fade very rapidly in this 
species, while in //elix nemoralis the normal dark lip is practically 
permanent, implying a much longer possession of the character.’ 
There is little doubt that food and environment do affect and modify 
the colouration of shells, and of this further confirmation is afforded by 
the experience of Capt. Farrer, who collected at York a number of half- 
grown specimens of the dark variety o/ivacea, which he reared to maturity 
at Bassenthwaite, feeding the animals on cabbage leaves and turnip ; 
and it is remarkable that the shell growth made under the altered con- 
ditions was abruptly changed in colour from a deep olive-brown to white. 
he protective resemblance of the shells of this species to other animate 
or inanimate objects has not been much remarked upon, except by Dr. Dall, 
who has suggested the possibility that the striped ornamentation of the 
Pentatenia would probably aid in their concealment amongst the lights 
and shadows of the vegetation, and lead one to attribute the genesis of 
these markings to similar causes to those that led to the development of 
the striped markings of the tiger; and by Captain W. J. Farrer, who has 
pointed out the extraordinary resemblance of the var. /utew to the closed or 
partially-closed flowers of the Lesser Celandine (Ranunculus ficaria), upon 
which plant they are found in numbers during April and May, affirming 
that it is difficult to distinguish the shell from the flowers, so much are 
they alike in form and colour. 
1 Monog. i., p. 329. ‘ 
103,11 \ 
