3040 THE Zoo.tocist—May, 1872. 
accept such paradoxes as arms (or legs) being part of the fool, and 
so forth. Still it is unquestionable that this garniture of arms or 
legs is neither more nor less than the exact representative of the 
smooth flat surface on which a snail glides, the only difference 
being that it is cut up into eight subequal divisions, all of which 
are prehensile. 
The dorsal surface is soft to the touch, but when pressed 
with the finger the hard bone or shell in the interior is very 
plainly to be felt, and is apparently very near the surface; the 
covering of the back I believe to be the homologue of the mantle 
in other mollusks, and its free margin, which scientific naturalists 
describe as “ two fins” because of its constantly undulating motion, 
is dilated continuously along the sides and is extremely flexible: 
it is fixed anteriorly, and partially covers the head like a Mary 
Stuart bonnet, and at the posterior extremity it has a sinus or 
notch. The colour of this mantle is chocolate-brown, with numerous 
transverse bars of a creamy whiteness: these are rather crowded 
and indistinct in the middle of the back; they are larger and 
beautifully distinct towards the margin, and are frequently once, 
and sometimes twice, divided before they reach the free margin of 
the mantle, which is entirely destitute of this peculiar decoration, 
but has very pale vermicular markings which assume the appearance 
of minute indistinct circles. 
The ventral surface is tumid and oval: its colour opalescent: as 
viewed from beneath it is wonderfully beautiful; its tint changes 
with every motion and almost every moment; it is absolutely im- 
possible to observe and describe any continuous tint, so fugitive 
are the shades. Moreover, in every part of the surface there is 
a rhythmical change of colour corresponding doubtless with the 
pulsatory action of the arterial system, which, of course, is con- 
cealed from inspection: the mouth, described as being situated in 
the midst of the legs, is also concealed; but there is a white funnel 
on the under side of the neck, and this also has a rhythmical motion 
corresponding with that of the changes in colour: this funnel 
seems to be used for the passage of excrement and also of ink, 
a vast quantity of the matter called by the latter name having been 
discharged on the morning of the lst of April, and thus affording 
an opportunity of observing a phenomenon which naturalists have 
rarely witnessed. The object of this discharge has hereafter to be 
considered: the explanation given by the philosophers that it is 
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