ADDENDA ET CORRIGENDA. #505 
and on the uppermost whorls these are barred by distant longitudinal 
threads, so as to form beads at the points of intersection, and disappear 
on the penultimate whorl. The last whorl is ventricose, with a 
siphonal beak constituting about one-third its length; on this whorl 
are six revolving ribs, the upper ones the largest, and undate nodose, 
rendering the whorl angular behind; they gradually diminish in size, 
until they become mere threads anteriorly; the interspaces are con- 
cavely excavated, not clathrate. Aperture a little more than half the 
length of the shell, lunate ovate; outer lip regularly arched and for- 
tified by a large rounded varix, over which the ribs run to the edge of 
the aperture; on the inside of the lip, which is dark chestnut-coloured, 
between each of the ribs, is a double plicate denticle ; inner lip arched 
centrally, chestnut-coloured, variegated with irregular white wrinkles, 
and also with one or two white lamina posteriorly. Beak slightly re- 
curved; colour, shades of purple brown; the varix about equally 
checked with three white and three brown portions. In the fresh 
state it is covered with a thin, fibrous, fawn-coloured epidermis, which 
at intervals of about a quarter of an inch rises into a fibrous or capil- 
lary fringe. 
Length two inches; breadth an inch and a half. Found on rocks 
at low water, in the outer harbour, Rio Janeiro. 
I have been rather minute in the description, as the shell appears 
to be one of several which have been included in the Linnean 7. 
doliarium. Deshayes has indicated it to be a distinct species, but has 
not described it. The colouring is like that of 7. doliartwm or suc- 
cinctum, but the more angular form and the cincture is like 7. cuta- 
ceum ; from this it differs in colour, and in the form and denticulations 
of the lip. The aperture and peristome resemble 7. pileare in form 
and sculpture, though the sculpture and colouring of the outer lip is 
different. It is intermediate between 7! pileare and T. cutaceum. 
Figure 296, the shell, a small specimen; 296 a, animal and shell, 
as in crawling; 296 d, foot of the animal, with the shell. 
kK 
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