INTRODUCTIOX, 
XI 
countenance to Dr. Zittel’s view that the siphuncle was originally 
a remnant of the visceral sac. A similar opinion was enunciated 
by Dr. H. AVoodward in his paper “ On the Structure of Camerated 
Shells,'*’ ^ in which after quoting Owen’s statement regarding the 
connection between the Xautilus 2^om_p{lius and its shell, to the effect 
that “ A third point of attachment is to the bottom of the shell by 
the posterior extremity of the mantle, which probably presents a 
conical form in the embryo Xautilus,” he continues, “ If then, the 
siphuncle in the young stage forms the main point of attachment 
between the animal and its shell, we may reasonably argue that the 
siphuncle in the adult Xautilus is simply the evidence of an aborted 
embryonal organ whose function is now fulfilled by the shell - 
muscles, but which in the more ancient and straight-shelled re- 
presentatives of the group (the Orthoceratites), was not merely an 
embryonal, but an important organ in the adult.” 
It has been observed, however, that the shell-muscles in Nautilus 
are incapable of bearing even a slight strain^. 
^ Popular Science Keview, vol. xi. 1872, p. 113, 
^ In proof of this the following interesting account of the behaviour of a 
living Xautilus, from recent observations, may be adduced. 
The account is taken from a “ Xote on the Pearly Xautilus,” contributed 
by Mr. Edgar A. Smith, F.Z.S. (Zool. Depart. Brit. Mus.), to the ‘ Journal of 
Conchology ’ for Oct. 1887, and runs thus: — “A specimen of Nautilus 
pilius, captured at Port Blair, Andaman Islands, has recently been presented to 
the British Museum by Mrs. E. Kenny, who has given the following account 
of its movements during captivity : — 
“ ‘ It was caught at the surface, near the anchor-cable of H.M.S. ‘ Osprey,’ in 
this harbour, in a fairly rough sea. The shell, when brought to me yesterday 
with the fish in it, appeared chipped and broken at the edge, from contact 
with the chain-cable. I at once placed it in a bucket of salt water (it had 
not been out of its element more than half an hour), and the fish seemed to 
begin to breathe strongly. The rough, skin-like covering to the mouth [the 
hood] of the shell appeared to rise, and on each side of it the gills commenced 
to work in regular pulsations. At the same time the tentacles were protruded 
in front, and gas or air was expelled, bubbling up at the surface of the water 
at regular intervals. The whole creature seemed to expand and grow looser, 
until quite suddenly it became detached from its shell entirely, and lay 
breathing or working at the bottom of the bucket. I may remark that once 
out of its shell, the fish showed no apparent desire to re-enter it. In the 
empty shell were seen a few small tadpole-like creatures, very active in their 
movements, whether parasites or not I do not know. These were washed off 
into a glass jar containing rum, and the fish was then put into the same jar.’ 
“ Unfortunately the specimen was placed in fresh spirit before the above notes 
were read, the so-called parasites being thus unconsciously thrown away with 
