: GEOMALACUS MACULOSUS. 255 
the remarkable elongation of the atrium or vestibule ; the long retractor muscle 
from the vesicle and its stem is affixed to the dorsum in the median line near 
the caudal end of the body; the vas deferens and the spermatheca open nearly 
Fic. 262. Fic. 263. Fic. 264. 
Sexual organs of Geowralacus maculosus, after dissections by Simroth (fig. 262), Godwin-Austen 
x 2 (fig. 263), and Scharff (fig. 264). 
ag. albumen gland; aé. atrium 3 of. ovotestis ; os.d. ovispermatoduct ; ef. epiphallus ; sf. sperma- 
theca ; v.d. Vas deferens : ; uv.s. vesicula seminalis; 7”. retractor. 
together into the distal ex- 
tremity of the ATRIUM, which 
is prolonged in an attenuate 
form to an enormous teneth, 
and receives the very thin free 
oviduet much nearer the proxi- 
mal end, where the muscular 
VESTIBULE is greatly but ir- 
recularly enlarged, and con- | 
nected to the oviduct by a fe 
niuinber of muscular fibres. 
Within the VAGINA there is a 
curious series of flattened folds, 
ria 
acaue 
Seorr tae 
— 
Sc 
the central part with pointed Fic. 265. Fic. 266. 
end, placed close to the genital Fic. 265.—Section of upper portion of Atrium x 8 
aperture, and which Godwin- after Simroth). 
Austen thinks may possibly be _ Fic. 266.—Internal structure of the vagina x 6 (after 
a SARCOBELUM and the homo- Godwin-Austen). g.a. generative orifice. 
logue of the dartin the Helicidie. 
The MANDIBLE, or jaw, 
ineasures about one mill. from 
side to side, and is distinctly 
arcuate from front to rear, 
Innate in shape, but very w ide, 
with broad and scar celyr ounded 
ends, solid, dark-brown in color, 
with about ten broad flat ribs, Fic. 267. Fic. 268. 
which are confined to the Mandible or jaw of Geomalacus maculosus to show 
median part of the jaw, and the variation in sculpture. 
absent or scarcely discernible Fic. 267._-Showing the denticulation of the upper margin 
on the side areas, sometimes x 20 (after Godwin-Austen). 
Fic. 268.—Showing denticulation of lower margin x 12. 
crenulating the upper and = Saisie a ee 
sometimes the lower margin or the ribs may extend quite across the jaw and 
denticulate both the upper and the cutting edges. 
