2 
margin of the mantle is lower than it ought to be, as it conceals in 
the natural state a great part of the funnel and the inferior half of 
the eyes. In regard to the last circumstance, the drawing of Lauril- 
lard given in M. Valenciennes’ paper is more correct; but in other 
particulars it is deficient, chiefly because the soft part of the integu¬ 
ments w r hich forms the visceral sac was torn off and wholly want¬ 
ing. It ought to be observed also, that those two figures represent 
the animal replaced in a shell of the same species indeed, but not 
its own. 
I suppose then that it may be perhaps of some interest to publish 
some drawings * I made, chiefly after two specimens, one of which was 
kindly presented to me in 1848 by Prof. Reinwardt; the other I re¬ 
ceived lately from our settlements in the East, by the kind exertions 
of His Excellency Mr. T. C. Baud, formerly His Majesty the King of 
the Netherlands’ Minister for the Colonial Department. 
The first figure (1) represents the animal from the left side in its 
own shell, which has been opened with a file at such a height, that 
the whole last chamber was visible, together wdth a part of the three 
following compartments. The hood (a), composed according to Prof. 
Owen by the conjunction in the mesial line of the two superior, ex¬ 
cessively large digitations, covers with its projecting margin the supe¬ 
rior surface of the pedunculated eye (5). The inferior half of the eye 
is concealed by the superior margin of the mantle, which covers also 
the greatest part of the digitations or lateral processes of the head (c, c ). 
The extremity of the funnel ( d ) is visible and uncovered, the rest 
being contained in the anterior part of the mantle. Ihere is no per¬ 
foration or excision at this part of the mantle j% but the margin of it 
is entire and slightly convex. 
The mantle (/, /, /', i) has its anterior part of a more thick and 
fibrose texture and a yellowish colour ; the posterior part (i) forms a 
thin and nearly transparent membranous sac, containing the different 
viscera. The free superior margin of the mantle ascends behind the 
hood (/') and forms the dorsal fold of Prof. Owen’s memoir; but at 
the side view only a small portion of this fold is visible. Beneath the 
posterior part of the hood, the mantle offers on each side a large apo¬ 
neurotic flat piece ( g ), of a bluish white colour and a kidney-like shape, 
being convex at its anterior side and somewhat concave at the poste¬ 
rior border. This plate is the posterior insertion of a strong muscular 
mass—the great muscle of the shell—which goes from this attach¬ 
ment in an oblique course, converging with that of the opposite side, 
to its anterior termination at the cartilage of the head. From this 
oblong patch arises a narrow aponeurotic stripe, both at the superior 
and at the inferior extremity of it. The oblong plate may be con¬ 
sidered as an expansion and development of this band, which, encir¬ 
cling the whole mantle, separates its posterior soft part or the visceral 
* The drawings, being on too large a scale for this work, will be published in 
the Transactions of the Society, vol. iv. PI. 5, 6, 7, 8. The references are to those 
plates.—D. W. M. 
t Professor Owen speaks of a large aperture through which the funnel passes. 
(Memoir on the Nautilus, p. 9.) 
