ORDER DEC APOD A. 
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or cephalic division in the form of a heart. ( Pagurus clypea- 
t-us, Fab.) 
Those which form the most numerous division, Pagdrds, 
proper, Latr., have, on the contrary, the middle antennae 
curved, notably shorter than the lateral, with the two threads 
short, and the upper one in an elongated or subulated cone. 
The anterior division of the thorax is squared, or in the form of 
a triangle inverted and curvilinear. ( Cancer Bernhardus, 
Linn.) 
A species inhabiting the Mediterranean should, from its 
peculiar characters, form a subgenus proper (Prophylax, 
Latr.) In these the tail, instead of being, with the exception 
of the upper of the three last segments, soft and arched, and 
having but a single rank of oviferous threads, is covered with 
coriaceous teguments, is directed in a straight line, and is not 
curved underneath, except at its extremity. Its inferior sur- 
face presents a furrow, and two ranks of false feet. The body 
besides is linear, with two lateral appendages at the end of 
the tail almost equal, and whose division is larger, foliaceous, 
and ciliated. The last four feet are slightly granular at their 
extremity, and appear to be terminated only by a single finger, 
or at least are not very distinctly bifid. Perhaps we must re- 
fer to this division, the paguri living in serpulas, alcyones, &c. 
In all the following macroura, the two posterior feet at most 
are alone smaller than the preceding. Most frequently the 
false subcaudal feet are five pair in number. The teguments 
are always crustaceous. The lateral fins of the penult seg- 
ment of the* tail, and its last one, form one in common, dis- 
posed like a fan. 
The two following sections have a common character, which 
separates them from the fourth. The antennae are inserted at 
the same height, or on a level. The peduncle of the lateral 
ones, when it is accompanied with a shell, is never entirely 
covered by it. The false sub-caudal feet are often but four in 
