HELICIGONA ARBUSTORUM., 419 
INTERNALLY, the PERICARDIUM is of dull grey, minutely spotted; the HEART is 
four mill. long, the AURICLE being grey, and the VENTRICLE of an opaque light 
grey. The GSOPHAGUS is white, the DIGESTIVE GLAND or liver is chestnut brown, 
and the OToCYSTS each contain more than one hundred otoconia. 
The CEPHALIC RETRACTORS as dissected by Miss Lebour show an almost 
common origin of the BUCCAL and 
TENTACULAR retractors ; the buccal 
strand is fairly long and broad, becom- 
ine bifid before attachment to the 
bueeal bulb, and somewhat basally gives 
off an auxiliary muscle to the left tenta- 
cular retractor. 
The right tentacular retractor is a 
strong strap-like muscle, which a little 
beyond half its length gives off from 
its inner side a strong divaricating 
branch to the anterior part of the foot, 
from the basal part of which branch the 
long, slender deeply pigmented muscle 
serving the anterior tentacle arises and ¢ 
also gives off a slender filament to the _ F!¢- 472.—Cephalic retractors of 17, arbustorum 
pee se Ieee vetractor in this prepara- x 2 (froma dissection by Miss Marie V. Lebour). 
i 1e le pre} 
tion differs from that of the right side, by the anterior tentacular branch being 
distinct and separate, and in giving rise to two separate bundles of powerful 
muscles directed to the foot. 
The REPRODUCTIVE ORGANS show the 
characteristic features of the Helicigone; the 
OVOTESTIS is placed in the early whorls of the 
shell, with the lobes of the liver or digestive 
gland; the pucr is rather long, at first 
simple and direct, but soon becoming tortu- 
ous and convoluted ; the ALBUMEN GLAND 
is narrowly linguiform and light buff in 
colour; SPERM DUCT light buff and much 
narrower than the oviduct; SPERMATHECA 
oval, duct or stem semitransparent and slen- 
der, but dilated basally; DIVERTICULUM 
thick, considerably longer than the sperma- 
theea and its duct, and bound to the uterus 
by a wide and richly vascular membrane ; 
VAGINA inflated below ; PENIS-SHEATH dis- 
tally thickened and comparatively short, 
continued as an EPIPHALLUS, and terminat- 
ing in a long and slender FLAGELLUM, which 
forms three complete spiral twists at its base 
—a striking peculiarity quite omitted in 
Moquin-Tandon’s illustrative figure; the 7 
long RETRACTOR MUSCLE is attached to the Fic. 473.—Reproductive or sexual organs 
median portion of the epiphallus and its distal of //edicigona arbustorum * Li. 
end fixed near the base of the mantle flap. alb.gl. albumen gland ; = dart SAC; sp. 
spermatheca ; sf.d. sperm duct; v.d. Vas 
The MUCUSGLANDS are paired, and enclose deferens; d. diverticulum ; ef. epiphallus ; 
between them the stylophore or dart-sac; they fi. flagellum ; m.gl. mucus glands ; ov. ovi- 
a/Pe AS - duct; of. ovotestis ; f. penis sheath; 7 penis 
are stout, stiff, simply subulate organs, vary-  etrattor. 
ing from 15-25 mill. in length, tough, as thick path 
as the dart-sac, and tapering to a blunt but occasionally bifid point, thus initiating 
the ramified organ of the true Helices; they vary in colour, and though white in 
immature individuals, when mature are usually grey, tinged with a dull shade of 
green, blue, purple, ochre, or even livid-brown, and besprinkled with minute spots 
or streaks of dusky-brown, a coloration sometimes shared by the dart-sac. 
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The sTYLOoPHORE or dart-sac is cylindrically clavate and whitish during growth, 
and only becomes pigmented as maturity is approached. Externally the sac is 
obscurely transparent-grey, and minutely spotted, but the internal walls may be 
purplish or reddish-brown, this colouring being perceptible through the outer 
envelope gives it the bluish-grey or livid aspect characteristic of the functionally 
mature sac, 
