PACKARD.] MORPHOLOGY OF PHYLLOPODA. 395 
homologized with the antenne, being true appendages. This is especi- 
ally seen in the cockroach and in Mantis tessellata (Guide to Study of In- 
sects, p. 17, fig. 23). 
The cercopoda.—We would suggest the name cercopoda* for the 
caudal appendages of the Phyllopoda, which are outgrowths from the 
telson. There seems to be no such appendages of the telson or anal 
arthromere in the Malacostracous Crustacea, as the uropoda are devel- 
oped on the segments anterior to the telson. But when we turn to the 
Entomostraca, we see that they occur, as a rule, in all Copepoda, where, 
in some genera (Pontellina, Zaus, Thalestris), they are two-jointed. 
These appendages then, in Copepoda, are true jointed appendages, arising 
from the end of the terminal segment of the urosome, and thus forming 
the last pair of abdominal appendages. In the order Branchiopoda 
the cercopods of the Copepoda are represented by the moveable, curved, 
slender, terminal claw ot the telson; and this form persists in the 
higher Limnadiade (Plate III, fig. 7; Estheria, Plate XXV, figs. 5, 6), 
being absent in Limnetis. The Jong, jointed, style-like candal append- 
ages of Apus are also the homologues of the Copepodous cercopoda, 
as well as of the Limnadiad claw-like appendage. In the larva, as seen 
by Dr. Gissler’s drawings, fig. 8, Plate XX XV, they are short and broad, 
and their cavity is continuous with the body-cavity. Late in larval life, 
as seen in fig. 9 of the same plate, a joint appears, and later on in adult 
life the cercopoda of the Apodide, as seen in Plate XVI, are nearly per- 
fectly jointed, with short, stout set arising from the edge of each joint. 
In the cercopoda of the Branchiopods we have reproduced quite ex- 
actly those of the Copepoda. So it appears that these appendages are 
restricted to the Entomostracous Crustacea, although they are also a 
characteristic feature of the Phyllocarida. 
Histology of the postoral appendages.—The male hands of the first 
pair in Hstheria and Limnadia present some peculiarities of interest. 
The finger-like two-jointed fifth endite of Hstheria mexicana (Piate XXV, 
fig. 3a, l’) is traversed by a thick nerve, which appears to originate 
from a multitude of nerve-cells, almost completely filling the distal joint. 
The latter when magnified by a Tolles + A eye-piece (fig. 3c) is seen to 
be filled with rather large nerve-cells (g c), which are arranged serially. 
Between the rows of cells are apparently fine nerve-fibers, which have 
not been so distinctly indicated by the artist as in my original drawing. 
These fine fibers appear to arise near the terminal cells (g ¢) and prob- 
ably originate in the seveu sete at theend of the joint. It is plain that 
this endite is the sensitive portion of the hand, though whether it is of 
apy special sense and other than tactile may seem doubtful. 
In Estheria compleximanus (Plate X XIX, fig. 5) and in the same joint 
of the fifth endite of the first pair of hands, when magnified by the 
same power (+ Tolles A), the main nerve is seen to traverse the joint, 
passing through a great number of very large nerve or ganglion cells 
(gc), which are not, however, arranged serially as in H. mexicana. ‘The 
nerve appears to break up into a number of fibers which probably in- 
nervate the numerous fine cilia-like sete at the end of the finger-like 
appendage. 
In the first pair of legs of Estheria compleximanus (Plate V, fig. 7) the 
sixth enditeis provided with nerve-cells and nerves which supply the seta, 
as seen in Plate X XIX, fig.3. Here the ganglion-cells are contained 
*We should also apply this name to the jointed anal stylets of insects such as the 
cockroach, Mantis, and other Orthoptera and Pseudoneuroptera, as well as the dipte- 
rous Chrysopila, and numerous other forms, 
