38 HYGROMIA REVELATA. 
Description.—The ANIMAL of a Guernsey specimen had a pale translucent 
yellowish-grey BODY, becoming darker grey above, the dorsum sparsely covered 
with irregularly shaped TUBERCLES, which become more rounded on the sides, 
giving the surface a granular appearance and showing in some lights faint longi- 
tudinal lineation, but the transverse furrows described by Dr. J. Gwyn Jeffreys 
were not detected, while the RETRACTORS are perceptible through the skin as dark 
subdorsal bands on each side of the body; the DORSAL GROOVES not distinct and 
enclosing a row of ill defined elongated tubercles; OMMATOPHORES rather thick, 
moderately long, and elongately bulbous at the end, of a translucent grey, and 
finely granulated ; the LOWER TENTACLES are only one-fifth the length of the 
upper pair, and somewhat enlarged basally. MANTLE yellowish-brown or whitish, 
faintly marbled or spotted with brown. 
SHELL subglobose in shape, very thin and translucid, usually slightly glossy, 
of a pale olive-green or greenish-umber colour, with a thick transversely wrinkled 
EPIDERMIS somewhat puckered at the sutures with somewhat irregular and more 
delicate intermediate strive ; the spiral sculpture is microscopic and formed by a 
close and beautiful series of distinctly incised striations, which gradually become 
abruptly undulate towards the umbilical region; and the whole surface is also 
beset with distantly rooted and erect or somewhat bent whitish hairs arranged in 
a forwardly directed, sinuously oblique series which cross the lines of growth ; 
WHORLS 4-44 in number, convex and swollen; SPIRE slightly raised, SUTURE deep; 
MOUTH ample, broadly semi-lunar, expanded and forming nearly four-fifths of a 
circle ; PERISTOME scarcely inflected above, slightly thickened and darkly margined, 
somewhat dilated basally and partially reflected around the narrow UMBILICUS. 
Diam., 7 mill. ; alt., 43 mill. 
Fic. 46. Fic. 47. Fic. 48. 
Fic. 46.—Periostracum of Hygromia revelata, showing arrangement of the hairs on its surface, 
after a drawing by Mr. G. Sherriff Tye (highly magnified). 
Fic. 47.—Periostracal hairs from the shell of Hygromia revelata, after a drawing by Mr. G. 
Sherriff Tye (greatly enlarged). 
Fic. 48.—Periostracal hairs from the shell of Hygvomia revelata, from Guernsey, from a micro- 
photograph by Mr. W. Bagshaw, x 59d. 
INTERIORLY, specimens from Guernsey showed a cream-coloured RENAL ORGAN 
and a dusky-brown LIVER or digestive gland, with an indistinct leaden-blue 
HEPATIC ARTERY. 
The ALIMENTARY SYSTEM possesses a very elongate GSOPHAGUS and relatively 
small and compact SALIVARY GLANDS with long slender ducts, showing a notable 
difference from those of the immature H. occidentalis from Tangiers, which display 
larger and less compact glands and quite short ducts, differences, however, which 
may be due to age or may be indicative of deeper divergence. 
The REPRODUCTIVE ORGANS show a creamy-white OVOTESTIS, & HERMAPHRODITE 
DUCT convolute and thickened below; ALBUMEN GLAND yellowish-white or ochreous- 
grey; OVIDUCT white and semi-transparent; SPERM—DUCT or prostate granulate and 
of a cream-white colour but variable in its width as in H.granulata; SPERMATHECA 
oval or pyriform, white when immature, flesh coloured when adult, the slender stem 
or duct as long as the oviduct, is thickened below, and originates just above the 
vaginal mucus glands; VAGINA broad, narrowing below, and in its natural position 
doubled upon itself; vaginal MUCUS GLANDS are nearly a millimetre in length, one 
on each side, both deeply divided sometimes quite to the base into two opaque 
cream-coloured branches ; the STYLOPHORES or dart-sacs are quite vestigial, and 
represented by two mere nipples when immature, but which are distinctly bifid 
when mature ; PENIS-SHEATH very narrow at the base, broadly swollen above; the 
EPIPHALLUS is somewhat fusiform ; the FLAGELLUM short, thick, subulate ; ‘the 
