220 The American Naturalist. [Mareh, 
THE CLASSIFICATION OF THE ARTHROPODA. 
By J. S. KINGSLEY. 
(Continued from page 135, February, 1894.) 
Sup-Crass [I—Evucrustaceka. 
Crustacea, with filiform, plumose or lamellate gills, in either 
thoracic or abdominal region; mouth parts never ambulatory 
in the adult, but modified for the prehension and comminution 
of food. Nauplius stage either free-swimming or passed in the 
egg. 
T is difficult, with our present knowledge, to find good 
diagnostic points separating the true Crustacea from the Trilo- 
bites, and it may be that further research will show that the 
latter are to be regarded as a division equivalent to some 0 
those mentioned below. At present, the arrangment of the gr 
of the cephalic region in a circle around the mouth, the use i 
their basal joints for the comminution food, and the apparel 
functioning of the distal joints as locomotor organs, together 
with the peculiar gills, must serve to differentiate the two 
groups, it being understood that the ideas here expressed are 
merely provisional. eo che 
In the sub-division of the Crustacea I am inclined to 4 a 
the recent “sub-classes” of Grobben (’92) as super-orders ; 
follows : 
Super-Order I, Phyllopoda. 
Order I, Euphyllopoda. 
Order II, Cladocera. 
Super-Order II, Estheriæformes. 
Order I, Ostracoda. 
Super-Order ITI, Apodiformes. 
Order I, Copepoda. 
Order II, Cirripedia. : 
Super-Order IV, i sive Branchipodiforme 
