AI2 Records of the Indian Museum. [Vor wills 
The blood channels in connection with the renal organ are 
regularized to some extent and are discussed in connection with 
that system. 
If one may infer from the arrangement of blood channels, 
the general course of the circulation would be from the heart 
via the aortae to either the head, foot, siphon, etc., or to the 
visceral mass. From the former to the general anterior cavity, 
thence via the renal organs to the anterior visceral sinus which 
presumably also gets the blood from the channels amongst the 
viscera (d above). ‘Thence to the mantle and ctenidium roof and 
so back to the heart. 
The separation of the sets of spaces is perhaps somewhat 
marked and one gets the idea of a fairly regular system allowing 
of course for movements of blood due to such other causes as the 
expansion and contraction of the foot, the protrusion and retrac- 
tion of proboscis and siphon, and so on. 
VI.—EXCRETORY SYSTEM. 
The renal organ is treated by Perrier who studied Voluta 
neptuni. It is situated on the right side of (that is, actually, be- 
hind) the pericardium (pl. xxix, fig. 3), and is a large massive organ 
occupying the lower part of the visceral mass and covered by the 
ovarian tubules. It consists of (1) the massive posterior or right 
lobe (see R. L., pls. xxix & xxxi, figs. 3, 1o—13), which has a spongy 
structure (pl. xxxi, fig. 15) and opens into the general renal cavity 
by fissures between some of its projecting lobes (pl. xxxi, figs. 12 
and 13). This lobe is wrapped around the rectum on the dorsal 
side of the latter. 
(2) The smaller anterior or left lobe (L.L., pls. xxix & xxxt, 
figs. 3, 10-13), a band of tissue of a lighter colour than the other 
lobe. It runs vertically, parallel to the posterior (morphologically 
right) wall of the pericardium. This band is, as it were, suspended 
from the roof of the cavity (pl. xxxi, figs. 11 and 12) and is at- 
tached to the floor just within the lips of the external openings (see 
fig. 12). Through this attachment it receives a branch channel 
(pl. xxxii, fig. 16, L.L.V.) from the great blood channel leaving 
the general anterior cavity (A.V.). The surfaces of the left lobe are 
somewhat swollen out, making numerous flat lobes with furrows 
between them (pl. xxxi, fig. 14). 
(3) The so-called nephridial gland (N. G., pls. xxix & xxxi, 
figs. 3 and 10—13) against the pericardial wall, but not extending 
over its (morphologically) anterior end. The internal surface is 
somewhat ridged and grooved and there are pits at intervals 
(pl. xxxi, fig." 13). 
The general renal cavity is partly subdivided by the vertically 
hanging left lobe as described. Just below the nephridial gland, 
and towards the right side (morphologically, forwards) the reno- 
pericardial canal (Rn. P.P., pl. xxxi, fig. 12) enters. The pericardial 
canal isshort and direct. The circulatory arrangements of the renal 
