8 NOTES ON 
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tinous tube, gradually tapering from the superior 
to the inferior extremity. The former or mouth 
is surrounded by a number of tentacula or 
feelers (a), arranged like rays around a centre. 
They are formed of a similar substance to the 
body, and like it are tubular. The number of 
these feelers, or arms, varies in different speci- 
mens from six to thirteen. 
The mouth (see 6, fiyure 2, &c.) assumes dif- 
ferent appearances as it is more or less con- 
tracted. It is not furnished with any appen- 
dages for mastication, and its form is sometimes 
that of a conical or truncated papilla; at others 
it is hollow, and has an aperture in the centre 
capable of great enlargement, for the reception 
of its prey, as shown in figure 4. 
The tail (c), which forms the posterior ex- 
tremity of the body, is slightly dilated for in- 
creasing the surface of attachment. Although 
it appears perforated, nothing is observed to 
pass, the refuse of the aliment being regurgi- 
tated. It seems only designed for attachment, 
and to assist the animal in changing its place. 
The whole internal surface of this animal 
performs the office of a stomach, or digestive 
organ. The food, when it consists of small 
pieces, and the nutritive juices when large, are 
