CRUSTACEA. 
174 
to the Gecarcin trois-eplnes , Desmar., a fossil species, Hist. Nat. 
des Crust. Foss,, VIII, 10; he suspects it may belong to the genus 
'llrelphusa. 
Here, at least in the females, the shell is very thin, membranous, 
and flexible, and the body almost round or subovoid. The ocular- 
pedicles are sensibly shorter than in the preceding subgenera. First 
comes the 
Mictyris, Lat. 
Wliere the body is subovoid, highly inflated, narrower, and more 
obtuse before, and truncated posteriorly; the clypeus considerably 
diminished, and its extremity narrowed into a point. The claws form 
an elbow at the junction of the third and fourth joint, the latter of 
which is almost as large as the hand ; the other feet are long, with 
angular tarsi. To these essential characters we will add, that the 
ocular pedicles are curved, and crowned with globular eyes ; that the 
external foot-jaws are vei-y ample, and their internal edge hairy, the 
second joint being very large, and the following one almost semi- 
circular. 
Two species are known : one is found in the Australasian 
Ocean*, and the other in Egypt t, where it was observed by M. 
Savigny. Immediately after these come the 
Pinnotheres, Lat. 
Very small Crustacea, which during a part of the year, in Novem- 
ber particularly, inhabit various bivalve shells, chiefly the Mytili and 
Pinnae. The shell of the females is sub-orbicular, very thin and soft, 
while that of the males is solid, almost globular and somewhat nar- 
rowed into a point before. The feet are of a middling length, and 
the claws straight and formed as usual. The external foot-jaws pre- 
sent but three distinct joints, the first large, transversal, and arcuated, 
and the second furnished at its internal base with a small appendage. 
The tail of the female is very ample, and covers the whole under part 
of the body. 
The ancients believed that they resided with the Mollusca, in whose 
shells they are found, on friendly terms, warning them of danger and 
seeking food for them. The inhabitants of certain districts, at the 
present day, attribute to their presence the unwholesome qualities 
sometimes manifested in the Mytili +. 
We now arrive at Crustacea, which, although analogous to those 
just mentioned in the insertion of their ocular pedicles, are removed 
from them in respect to their shell. It is heart-shaped, and trunca- 
ted posteriorly, elevated, dilated and rounded on the sides near the 
anterior angles. The ocular pedicles are shorter than those of the 
* Lat., Gener. Crust, et Insect., I, 40 ; Encyc., Method., Atlas d’Hist. Nat. 
ccxcvii, .3 ; Desmar., Consider., XI, 2. This subgenus, and that of the Pinnotheres, 
in the first edition of this work, constituted part of the Orhicularia ; but in their 
natural order they approach the Ocypodes, Gecarcini, &c. 
-f- PI. d’Hist. Nat., of the great work on Egypt. 
J For species see Leach, Malac. Podopli. Uritt., and Desmar., Consider. G(^n^r. 
sur les Crust., 116 . 
