of Spirula australis, Lamarck. 7 
u urocardial” chamber, containing the (supposed renal) venous 
follicles (ib. cl , cl). 
Viewing the viscera from the left side (PI. II. fig. 3), one 
sees the large and few convolutions of the wdde oviduct (e) 
crammed with ova, of a deep yellow colour, four or five on the 
same transverse line : the last long recurrent fold advances 
over the liver, between the last chambers of the shell and the 
converging masses (ib./*) of the retractors of the head and 
funnel; these enter, overlap the margins, and send an 
aponeurosis over the exterior of the last chamber of the shell 
( u ). The above parts are on the dorsal aspect; on the ventral 
one are the gills and the succenturial or nidamental glands. 
Reflecting back the oviduct we expose the right lobe of the 
liver, impressed by the impacted ova in the duct which over¬ 
lay that lobe. 
The visceral chamber is bifid posteriorly, through the for¬ 
ward intrusion, at the median line, of the last whorl of the shell 
and the mass continued from its last chamber (PI. II. fig. 2, z). 
The branchiai are attached to the membrane reflected from 
each side of this intrusive mass *. 
The peritoneum after lining the mantle is reflected, on the 
dorsal side, 4 millims. below the edge of the pallial valve, upon 
the last chamber of the shell, and is firmly united to the peri- 
ostracum on that side of that chamber ; a crescentic portion is 
continued from the shell upon the sides of the muscular attached 
mass. 
The inner surface of the peritoneum is smooth, of a dull 
silvery glistening colour, without pigment. 
The tissue of the urocardial walls includes a stratum of very 
numerous, fine, smooth fibrils, together with capillary vessels, 
ramifying with some regularity. 
The retractores infunclibuli (PI. I. fig. 4, t\ PI. II. fig. 1 ,/) 
pass obliquely distad and dorsad to join the retractores capitis, 
where these enter, or are attached to, the last shell-chamber. 
From this part the peritoneum, extending ventrad, sends off 
the u mesobranchia ” and envelops the gill, from which it 
is continued upon the free termination of the oviduct and 
oviducal gland (PI. III. fig. 6, d) ; it is then continued over 
the pericardium and upon its valvular outlet, and upon the end 
of the rectum, before being reflected to gain the inner surface 
of the mantle. 
On the ventral side of the visceral chamber the nidamental 
glands (PI. III. fig. 1, c, a) occupy nearly the same relative 
position as in the Nautilus , but, as in Decapods, are not 
adherent to the mantle. 
* See u Monogr. on Spirula,' up. at. pi. iv. fig- 11. 
