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CLASS CRUSTACEA. 
Bipeltata, 
Has the testa divided into two bucklers, of which the ante- 
rior, very large, more or less oval, forms the head, and the 
second, corresponding to the thorax, transverse, and angular 
in its outline, carries the jaw and ordinary feet. These feet, 
with the exception at most of the posterior two, and the last 
two jaw-feet, are slender, filiform, and for the most part very 
long, and accompanied with a lateral ciliated appendage. 
The four other jaw-feet are very small, and conical. The 
base of the lateral antenna} presents no scales. The middle 
are terminated by two threads. The ocular pedicles are long. 
The body is very much flatted, membranous, and transparent, 
with the abdomen small, and without spines at the posterior 
fin. 
This family comprehends but a single genus, that of 
Phyllosoma, Leacli. 
All the species belong to the Atlantic Ocean and the Eastern 
Seas. With reference to their nervous system, they seem to 
be intermediate between the antecedent Crustacea and those 
which follow. 
OF THE MALACOSTRACA, WITH SESSILE AND 
IMMOVEABLE EYES. 
The branclripes will be, from this point, the only Crustacea 
which present us with eyes carried on pedicles ; but besides 
that these pedicles are not articulated, nor lodged in special 
cavities, these Crustacea have no carapace, and are also re- 
mote from the preceding by many other characters. All the 
malacostraca of this division are alike destitute of carapace. 
Their body, from the head, is composed of a series of articu- 
