MOLLUSCA OF INDIA. 229 
Helicarion (sec. B) gigas, Theob. Supp. Cat. p. 23. 
Austenia gigas, Nevill, Hand-list, p. 16. 
Helicarion (sec. B) gigas, Pfeiffer, ed. Clessin’s Nomen. Helic. 
Vivent. p. 30. 
Locality. Teria Ghat, Khasi Hills. 
Shell ovate, broad, depressed ; body-whorl large and expanded, 
with a shining lustre, quite smooth, excepting the irregular lines of 
growth ; colour olivaceous, with sienna-brown, paler at the apex, 
somewhat nacreous within (one specimen is entirely sienna-brown, 
and milky white within); apex flat; whorls about 12; columellar 
margin very short and very oblique. 
Largest specimen: maj. diam. 1°7, min, 1:2 inch (=42°5 and 
30 mm.). 
Another: maj. diam. 38°3, min. 24:5 mm. 
3 53505, 0:96 inch. 
“ Animal.—The left dorsal lobe * (U.d.0. plate xxiv. figs. 3, 4, 5) 
is large in front, and extends from the respiratory orifice to the leit 
margin. The right dorsal lobe (r.d./.) extends from the same part 
to the posterior right margin. The shell-lobes are connected all 
round the periphery of the mantle-zone, but are reduced in size, and 
present two distinct right and left contractile lobes; the mght 
extends to and covers the apex of the shell, while the left extends 
over the edge of the body-whorl for a distance of 0°3 to 0:5 inch, 
leaving the posterior and the greater portion of the upper surface of 
the shell uncovered (we have here a true approach to what is seen 
in the subgenus Macrochlamys). The posterior margin of the shell 
is not sunk in a depression of the hinder part of the foot, but the 
upper surface of the foot extends in an unbroken ridge to the mantle- 
zone.” 
In Plate LY. figs. 3 and 3a, the animal is shown with the shell 
removed; fig. 36 gives the position of the shell-lobes viewed from 
behind; the apex of the shell and all it contains sliced off. 
«« Extremity of the foot truncate, with a large linear mucous gland, 
the pedal line very distinct, as well as the lateral markings on the 
surface of the body. 
“ Genital aperture at the lower and outer base of the right tentacle. 
« Animal reaches quite 4 inches in length. 
“Description of Genital Organs of A. gigas.—Small var., Khasi Hills 
(plate xxv. fig. 1).—The ovo-testis was not seen ; the hermaphro- 
dite duct (h.d.) is much convoluted at the anterior end, where it 
divides ; the shape of the albumen-gland was also unobserved, and 
had apparently not been preserved in the spirit. The oviduct (ov.) 
was yery closely convolute, and arranged in four sharp folds upon 
the posterior portion of the spermatheca (sp.), to which it is appa- 
rently held by muscular tissue. The prostate is wide, regular, and 
ribbon-like, much and closely convolute, giving off the vas deferens 
not far above the junction of the spermatheca with the oviduct ; this 
* Refers to paper and plates in P. Z. 8. 1880, pp. 289-299. 
