14 Mr. Swainson’s Description of 
perfectly tubular; these spines are very thin, and are placed parallel 
with and very near to the aperture; their summits are obtuse and 
their length variable, probably owing to some having been injared 
through their great delicacy; the longest measured nearly one- 
eighth of an inch; from the summit of each spine emerges two 
stiff erect acute bristles; closely adhering together, and projecting 
about two-tenths of an inch. The colour of these bristles is black, 
their surface polished, and their substance horny. They likewise 
possess some degree of elasticity, being easily bent by a slight 
pressure applied laterally ; although I doubt whether they would 
have sustained such pressure had it been applied horizontally. 
These bristles it will be perceived, are completely sheathed at their 
base by the tubular spines, but these latter are so thin that the 
lower part of the bristles are distinctly seen through them; rooted, 
as it were, in the substance {of the shell. I know not, positively, 
whether each spine contains ¢wo distinct bristles; or only one, 
forked or divided at about half its length, as this fact could only 
be ascertained by removing one of the spines, and tracing how far 
the division extended; but that portion which forms the lower 
half (and is enclosed within the spine) is so thick, as to favour the 
supposition of their being in pairs. These spines are continued 
round the middle of each volution of the spire to its apex ; but they 
are more remote, and the bristles much shorter, than those on the 
body whorl; sometimes, indeed they hardly project beyond the 
spines. The direction of the whole is slightly incurved. The 
aperture is pale; and, at the top of the outer-lip, is an indented 
sinus similar to that seen in M. amarula, Lam. 
Ob. 1. The extraordinary appearance of bristles protruding from 
the spines of a shell, a formation altogether unprecedented amongst 
this class of animals, might naturally excite, in some minds, a sus- 
picion that it was an ingenious deception. But this idea, I think 
will be abandoned, when the peculiar construction of the spines 
are well considered. In the genus voluta, we have many instances 
of shells being crowned with thin, vaulted spines, but no example 
can be produced, of such coronated spines being tubular; or com- 
pletely closed in their circumference, and pervious only at their 
