144 XEROPHILA VIRGATA. 
This species is very variable in the size and shape of its shell, also in 
its ground colour, and in the disposition and colour of the banding, and 
has, therefore, been split up into a great number of species, most of 
which have no structural basis and very many are probably slight and 
quite unimportant modifications. 
Dr. Pilsbry and others regard Y. variabilis of Draparnaud as specifically 
distinct from _X. virgata Da Costa, while others, including Moquin-l'andon, 
claim that the Helix maritima of Draparnaud is more or less entitled to 
separate acceptance. Dr. Pilsbry also considers that H. burdigalensis 
Grateloup, H. grannonensis and H. lauteretina of Bourguignat, H. mend- 
ranot Servain, H. salentina Bl., and H. striata Brard should be regarded 
as synonyms. 
Diagnosis.—ExTERNALLY, Yerophila virgata differs from Helix pisana, 
with which it is frequently confused, by its smaller size, more prominent 
spire, wider umbilicus, and by the absence of the finely incised spiral 
lineation so characteristic of that species. 
From XY. caperata it differs by its shallow and irregular striation, so 
different from the distinct and more regular rib-like strize of that species ; 
it is also more globose in shape, and has a narrower umbilicus. 
From. ztala it may be easily distinguished by its more globose shape 
and narrow umbilicus. 
INTERNALLY, it differs from H. pisana by the complete freedom of the 
right tentacular retractor from the sexual complex, by the much simpler 
character of its gypsobelum or love-dart, and by the more numerous 
transverse ribs upon the mandible. 
From 1. caperata and X. heripensis it differs in its more bulky stylo- 
phore, which is sometimes cleft at the apex, as well as by the longer stem 
to the spermatheca, which has also a smaller terminal sac or vesicle. 
From XX”. itala it is separated by having only one love-dart instead of 
the two found in that species. 
Description of Shell.—SHELL subglobose, spire somewhat raised and conical, 
base convexly rounded ; of an opaque whitish or yellowish colour; rather solid 
and glossy, with fine but somewhat irregular striz and a few scattered malleations. 
WHORLS 5-6 in number, rounded at the periphery in adults, though sharply keeled 
in the young, and increasing gradually in size, but inflected on approaching the 
mouth, the whorls being separated by a distinct suture, and ornate with darker 
spiral banding, which typically consists of a broad zone above the periphery and 
seven more slender ones beneath as in Da Costa’s figure. UMBILICUS narrow but 
deep. APERTURE obliquely lunate ; PERISTOME simple, with a thickened internal 
submarginal RIB, which may be whitish or tinged with reddish-brown, and 
approaches most closely at the basal margin of the aperture, which is slightly 
dilated over the umbilicus. Diameter, 20 mill. ; altitude, 8 mill, 
The EPIPHRAGM is delicate, transparent, colourless and somewhat iridescent. 
with a small circumscribed opaque-white area, opposite the respiratory orifice, and 
formed by a dense deposit of calcareous particles. The epiphragm is attached 
basally close to the margin of the aperture, but the line of fixation gradually 
becomes more internal, until at the junction of the outer lip with the penultimate 
whorl it may be sunk 3-5 mill. within the aperture of the shell corresponding to 
the position of the internal rib. 
The winter epiphragm is described as being often thicker, opaque, and whitish. 
Description of Animal.—Numerous specimens collected in August, 1917, at 
Hunmanby, Yorkshire, by Mr. G. Fisher, had a somewhat elongate BoDy, blunt 
in front, the TAIL keeled and tapering behind, and projecting well beyond the shell 
when crawling. The body was closely tuberculate, of a somewhat translucent 
greyish creamy-white, or even quite colourless behind and below the position of 
the TENTACULAR RETRACTORS; the pigmentation, which varied from pale grey to 
