562 SUPPLEMENT 
with a simple, rounded, medial orifice, usually very large, 
surrounded, or not, with appendages of variable form. The 
union, in a greater or less portion of their edge, of these buccal 
appendages, constitutes a common pedicle, the cross-wise at- 
tachment of which divides the orifice into four parts. 
The hemispherical, and principal portion of the body, is 
termed, as we see in the text, wmbrella. The buccal append- 
ages are called arms. ‘The part composed by their union is 
called pedicle. j 
The umbrella, always regularly circular, is sometimes very 
much depressed above, as itis underneath. At other times 
it is subcylindrical from its great elevation. It is rarely 
globular, finally, and most frequently it is nearly hemispheri- 
cal. Its edges, or the line of junction of the convex with the 
concave part, are sometimes entirely smooth, rarely raised 
into angles, a little salient, or sub-lobate, or tuberculous. 
Most frequently they are furnished with tentacular filaments, 
more or less elongated, and which have been called tentacula. 
We remark, also, in a certain number of species, in different 
points of the circumference of the umbrella, similar organs, at 
regular intervals, the use of which is unknown. They are 
designated by the name of auricles. The aperture of the 
middle of the concave face is sometimes very great, round, 
or squared. It is sessile, or at the extremity of a sort 
of labial elongation, in the form of a proboscis, or funnel, 
more or less elongated. In the circumference of this aper- 
ture, whether sessile or not, are often remarked appendages 
or arms, sometimes rather long, of a fixed number, and which 
are divided or ramified in all their extent, or at their extremity 
only. Between these divisions are sometimes seen some 
organs which Pallas and Peron have compared to the cotyle- 
dons of vegetables. These appendages are often attached to 
the circumference of the sessile mouth, and sometimes more or 
less high on the proboscis. But it sometimes happens that 
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