HELIX NEMORALIS. oo 
Diagnosis.— Helix nemoralis may be distinguished from H. hortensis 
by its larger, thicker, and more depressed shell, which usually possesses 
half-a-whorl more than its ally; the surface is also less glossy; and the lip 
and callous deposit on the penultimate whorl are stronger and of a per- 
manent brown or black, differing in this from the dark-lipped form of 
H. hortensis, in which species the dark pigmentation of the lip gradually 
fades on exposure to light. The disposition of the bands is also different, 
as they are placed somewhat lower on the shell, the basal bands thus 
encircling the umbilical region more closely, and approximating in this 
respect to Helix wustriaca. 
INTERNALLY, the gypsobelum or love-dart is an undeniable and unfailing 
criterion of their specific difference, the dart of the present species differing 
strikingly from the dart of its ally and closely resembling that of 17. wspersa, 
while the dart of A. hortensis is of quite a different type, having most 
affinity with that of H. pisana. 'The vaginal mucus-glands are also per- 
ceptibly different, those of 7. nemoralis being usually less ramose with the 
digitations quite uniformly cylindrical throughout; while those of /Telia 
hortensis have more numerous digitations and are also irregularly tumid 
towards the extremities. 
Description. —The ANIMAL is of moderate bulk, usually of a leaden-grey, with a 
yellowish or greenish tinge, becoming darker with age; the surface is noticeably 
tubereulate, with a pair of longitudinal furrows along the centre of the back, 
which contain a row of elungate and usually paler TUBERCLES, rendered more 
perceptible by the darker shade of the subdorsal area; the LATERAL GROOVES are 
present and quite perceptible; MANTLE usually pale yellow, studded along the 
free margin by the pigment glands which are similarly arranged to the banding 
characterizing the shell; TENTACLES long, rather slender, tapering, and divergent, 
nearly cylindrical, with well-marked bulbous extremities, very delicately tuber- 
culate ; lower tentacles short and cylindrical. 
SHELL subglobose, very convex above and less so beneath; with very fine but 
irregular strive of growth, and delicate spiral lineation, which gives to aged shells a 
somewhat malleate aspect; thin, rather solid, subopaque, smooth, and somewhat 
glossy, typically yellow, with five narrow dark-brown spiral bands, but varying to 
white, red, fawn, brown, or even to lilae, with one to five bands, which are ocea- 
sionally confluent or interrupted, and assume a great variety of colouring, or may 
be perfectly colourless and transparent. Spire, five-and-a-half regularly increasing 
convex WHORLS; SUTURE not deep; APEX raised; APERTURE very oblique, deeply 
crescentic, and interrupted by the penultimate whorl ; PERISTOME interrupted and 
slightly reflected, the OUTER LIP noticeably inflected above, but slightly angular 
helow, bending abruptly towards the columellar margin, usually brown-black 
(though varying to many diverse tints) with a submarginal rib of the same colonr: 
inner lip tinged with the colour characterizing the outer lip; UMBILICUS open and 
deep in the young, but becoming closed in adult life. 
Fic. 328. - Fic. 329. 
Fic. 328.—Helix nemoralis L., showing typical form and banding. 
Fic. 329.—Helix nemoralis L., showing in sit# the thin, iridescent, summer epiphragm, and the 
white calcareous thickening in front of the respiratory orifice. 
Diam. 20 mill.; alt. 15 mill. ; average weight about 10 grains, and the thickness 
of the shell towards the aperture is between one-third and one-tenth of a millimetre. 
The summer EPIPHRAGM is quite flat, smooth, thin, transparent, and glistening, 
with an opaque and calcified area nearly opposite the respiratory orifice, but the 
hibernal one is usually thick, opaque, and somewhat cretaceous, with one or more 
thinner films behind, separated from each other by a perceptible space. 
