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From the American Journal of. Science and. Arts, 2nd. Series, Vol. XI.—May, 1851. 
E 
ON THE É 1BRAE B 
w 
CLASSIFICATION 
OF THE. 
MAIOID CRUSTACEA 0R OXYRHYNCHA. 
By JAMES D. DAN A. 
Tur Maroipza are usually divided into three tribes, characterized 
by the relative lengths of the legs, viz., the Macropodinea, the Maiinea, 
and the Parthenopinea. .À character of the kind here alluded to is 
of little importance as a distinction in classification, unless it is indi- 
cative of other more fundamental differences. "The third of these sub- 
divisions seems to be properly and distinctively a natural group. But 
the first two are essentially identical in all points, excepting the greater 
or less elongation of the eight posterior legs. 'l'he mouth, the antennz, 
eyes, branchiz, and other parts, afford no ground for separating them : 
moreover, the transitions are gradual and numerous.  Libinia and 
Doclea pass into one another through Libidoclea, and these three genera 
are more closely related than. Doclea and Inachus. Eurypodius con- 
tains a species with short legs; and the genus Oregonia, very near 
Eurypodius, has no longer legs than some of the admitted Maiinea. 
The mere length of the legs, if regarded, thus breaks up true natural 
groups. 
De Haan sustains the separation of the Inachide (Edward's Macro- 
podinea, Doclea and Latreillia being excluded.) on other grounds, ac- 
knowledging the unimportance of the characteristic derived from the 
legs. Asin other departments of Crustacea, he basis his distinctions 
mainly on the maxillae or maxillipeds. 'hus his Maia, Pisa and Doclea 
groups include species having the fourth joint of the outer maxillipeds 
articulated with the inner apex of the third joint ; while in his Inachus 
group, the articulation is with the summit of the third joint. "This distinc- 
tion would separate the intimately related genera Eurypodius andOregonia, 
as this joint in the latter has the ordinary Maia form. On examining 
Eurypodius it is found. that the peculiarity of the third joint referred to 
arises simply from its being lengthened or extended along the inner 
SEOOND SERIES, Vol. XI, No. 33.—May, 1861. 64 
