™/. 
142 ZONITOIDES NITIDUS. 
Description—ANIMAL with a long, slender, and very lubricous BoDy, of an 
almost uniform deep slaty blue-black colour; DORSAL FURROWS distinct, and 
enclosing a row of broad and well-defined tubercles; the tubercles of the body 
generally are large, flat, and indistinct, dusted over with whitish specks, and 
broken up by several longitudinal, somewhat divaricatine furrows on each side 
of the dorsal line ; MANTLE grey, finely spotted with black ; TENTACLES granulate, 
long and somewhat slender when fully extended; EYE spECcKS black; lower 
tentacles very short and swollen at ends. 
SHELL convexly rounded above, flatter beneath, of an almost uniform bright 
reddish-brown colour, without any whitish basal opacity, very glossy, with strong 
and numerous transverse strive which are stronger and somewhat puckered at the 
suture; WHORLS five, convex, the last noticeably wider than those preceding ; 
SPIRE raised ; SUTURE deep; APERTURE forming about three-fourths of a circle ; 
OUTER LIP thin, and only very slightly reflected around the deep, moderately-wide 
and funnel-shaped UMBILICUS which exposes all the interior of the spire. 
Diam., 8 mill. ; alt., 4 mill. 
When containing the living animal, the shell presents an uniformly dark chocolate- 
brown appearance with a duplex darker margin to the aperture. 
INTERNALLY, the NERVE RING consists of large and 
white SUPRA-CESOPHAGEAL GANGLIA, closely approxi- 
mate but connected by commissure; the PEDAL GANGLIA 
are greyish and fused together, the orocysrs showing 
up as white specks on their posterior face ; the VISCERAL 
LOOP contains the typical five components, the ABDO- 
MINAL GANGLION being the largest, and fused with 
the right pallial centre, which is noticeably larger than 
its fellow on the left side, an unfailing indication of dextral organization. 
Fic. 191.— 
Renal organ 
and heart of 
Z.nitidus X10 
a. auricle; 
v. ventricle 
k. kidney. 
The REPRODUCTIVE SYSTEM shows an elongate OVOTESTIS with compact acini, 
and the HERMAPHRODITE DUCT is somewhat sinuous in 
its course ; the ALBUMEN GLAND is lineuiform, formed 
of closely appressed lobules, and of a clear brown or 
yellowish-grey colour, with minute milk-white specks ; 
this gland is as usual only slightly developed in the 
young, but acquires considerable dimensions in adults, 
especially at pairing time; the VESICULA SEMINALIS or 
claw is oblong and greyish-brown in colour ; OVIDUCT 
or uterus ligit grey and distinctly sacculate ; FREE 
OVIDUCY direct and stout, with a greenish glandular 
investment ; the PENIS SHEATH is dilated and bulky 
basally, and contains a caleareous channel-shaped organ 
with a distinct rim or collar at one end, whose function 
is unknown, but which only exists in conjunction with 
the dart ; distally the penis sheath abruptly contracts, 
and probably constitutes an EPIPHALLUS, from whose 
free end the VAS DEFERENS and RETRACTOR MUSCLE 
arise ; SPERMATHECA pyriform and yellowish with a 
long and slender stem which divides below, the most 
direct and slender branch enters the base of the free 
oviduct, the other and larger 
duct, according to Pelseneer, 
opens into a closed space sur- 
rounding the penis sheath ; the 
DART SAC is elongate, whitish 
and semitransparent, with a re- 
curved and rounded extremity, 
but when immature is of a 
digitiform shape without any 
trace of the pendant coronal 
gland which is so conspicuous 
at maturity; the DART is a 
Fic. 192.—Gypsobelum or 
dart of Z. nitidus x 10, 
side view and front view. 
Fic. 193.—Sexual organs of 
Z. nitidus X 3, showing the 
arrangement of the organs and 
the position and character of 
the dart and dart-sac, the cal- 
careous penial channel, etc. 
a.g. albumen gland ; d.s. dart 
sac, showing dart and subapical 
coronal gland ; ov. oviduct ; of. 
ovotestis ; #. penis sheath, show- 
ing position of calcareous collar ; 
pr. prostate ; sf. spermatheca, 
showing the bifurcate stem; 
v.d. vas deferens. 
delicately curved filiform weapon, of a glistening white 
colour, without blades or annulus, and is deseribed by Dr. 
Lehmann as possessing an expanded base and somewhat 
lanceolate head, as in Z. evcavatus, but I have not been fortunate to find one 
answering that description. 
