12 
BRITISH ENT0M0STRACA. 
M. Milne Edwards, in his excellent work on the Crus- 
tacea,* adopts the organization of the mouth as the basis 
of his arrangement also. He divides the great class 
Crustacea into three sub-classes. The first two of these 
have an apparatus especially provided for laying hold of 
the substances destined for their food; while the third 
has no such special organization, their masticatory organs 
being the same as their organs of locomotion. The first 
sub-class is that of the Maxilles, or those whose mouth 
is furnished with organs for mastication. The second is 
that of the Sugeurs, or those whose mouth is furnished 
with an apparatus for sucking ; and the third is that of 
the Xyphosuriens, or those whose organs of motion are 
the same as the organs of mastication, and which differ 
in many other points also from the first two. The 
Maxilles he again divides into four legions : 1st, Podoph- 
thalmiens, containing the orders Decapodes and Sto- 
mapodes; 2d, Edriophthalmes, containing the orders 
Amphipodes, Isopodes, and Lsemipodes ; 3d, Branchio- 
podes, containing the orders Cladoceres and Phyllopodes; 
and, 4th, Entomostraces, containing the orders Ostrapodes 
and Copepodes. In this arrangement, the last tw r o 
legions of the Maxilles, the Branchiopodes and Entomos- 
traces, correspond exactly with Latreille’s first order, the 
Branchiopoda, and form a very natural group. The sub- 
class Sugeurs, he divides into two legions, the Parasites 
nageurs, containing the orders Siphonostomes and Ler- 
neens ; and the Parasites marcheurs, containing the order 
Araneiformes. The last sub-class, the Xyphosuriens, con- 
tains the single order Xyphosures. In this method we 
see the Lernese constitute a portion of Latreille’s Peecilo- 
poda, into which they were refused admittance by him. 
They were placed by Cuvier, in his ‘ Regne Animal/ 
amongst the Zoophyta, and in general, till within a few 
years, they were classed by naturalists amongst the 
Vermes. Desmarest showed the relations they had with 
* Hist. Nat. des Crustaces ; suites a Buffon, 1834-40. 
