SYSTEMATIC ARRANGEMENT. 
The systematic arrangement of the Crustacea has been 
a matter of considerable discussion amongst naturalists. 
Desmarest, in his work,* has given a series of tabular 
views of the various arrangements which different authors 
have suggested, from Linnaeus to his own time. For a 
complete view of these we refer the reader to him, and 
shall only notice a few of the more prominent here, as far 
as the Entomostraca are concerned. 
Linnaeus places the Crustacea in the class Insecta, 
order Aptera, and refers all the species of Entomostraca 
then known, with the exception of two, to one genus, 
which he calls Monoculus. Eabricius also places the 
Crustacea amongst the Insecta ; the genus Monoculus, 
embracing most of the Entomostraca, being placed in 
his Class vm, Polygonata, and the genus Limulus in the 
ixth, Kleistognatha.f 
Muller, following his predecessors in arranging the 
Crustacea amongst the Insecta, places of course the Ento- 
mostraca in that class also.J He divides them into 
two great sections, according to the number of eyes, viz. 
Monoculi and Binoculi. These he subdivides again into 
Univalves, Bivalves, and Crustacei, according to the form 
of the shell or covering in which the animal is inclosed. 
Latreille^ and Cuvier, || in their first published Methods, 
also placed the Crustacea amongst the Insecta, the former 
adopting the arrangement of Muller with regard to the 
Entomostraca, and dividing them into two families, the 
* Consid. gen. sur les Crustaces, 1825. 
f Systema Entomologise, 1775 ; Entomologia Systematica, 1793. 
X Entomostraca, 1785. 
§ Precis des Caracteres gen. des Insectes, 1796. 
|| Tableau element, de l’Hist. Nat. des Animaux, 1798. 
