. MR. LUBBOCK ON SOME FRESHWATER ENTOMOSTRACA. 205 
Common in ponds in Kent. 
It is generally colourless, but often red. 
The females carry their egg-sac in spring and autumn, and generally float in a more 
or less perpendicular position. 
Length x; of an inch. 
DIAPTOMUS CASTOR, Jurine. 
The anterior antennz are shorter than the body. The apical seta on the anterior side 
of the twenty-third segment is large (Pl. XXXI. fig. 7 a), while in D. Westwoodii it is 
quite small (fig. 1a). The right anterior antenna is very much like that of the pre- 
ceding species ; but a careful comparison of the figures will show several slight differences : 
for instance, there is in D. castor no tooth at the apex of the twenty-fourth segment. 
The inner branch (Pl. XXXI. fig. 11 a) of the fifth pair of legs is in the female 
cylindrical, and consists of two well-marked segments. At the apex it bears three 
spines—one small, one large, and one of middle size. The large one is spinose. The 
outer branch is much larger. The inner margin of its second segment (b) is produced 
into a great spine; hence it comes to pass that the terminal portion of the branch (c) is 
apparently situated, not at the apex, but on the outer margin and not far from the base 
of the second segment. Unlike as this branch is to the corresponding organ in the other 
species, it is easy to see that it is composed of the same parts. 
The fifth pair of legs in the male (Pl. XXXI. fig. 10) do not differ so much from 
those of the other species; they are, however, somewhat longer in proportion. The 
inner branch (a) of the right leg is two-jointed. 
The posterior segment of the cephalothorax and the first of the abdomen resemble the 
figure given by Liljeborg (J. c. pl. 18. fig. 6), but the posterior angles of the cephalo- 
thorax are less expanded, and the angle a was in my specimens rounded off. These 
parts are somewhat unsymmetrical. 
Colour reddish. 
With the preceding, in Kent. The females carry their eggs in April. 
Length 45th of an inch. 
APODID.E. 
LEPIDURUS PRODUCTUS. 
The genus Lepidurus was founded by Leach. It differs from 4pus in having the 
posterior segment produced into a plate or flap which lies between the caudal filaments, 
and in the shortness of the anterior legs. The species of this family, though found in 
large numbers wherever they do occur, are yet but seldom met with, and until last year 
I had never seen any of them alive. i 5 
During a visit to the north of France made last spring with Mr. Prestwich and 
Mr. Evans, principally in order to compare the river-gravels of the Seine valley with 
those of the Somme, we fortunately chanced to visit, among many others, a gravel-pit 
at Pont del'Arche,near Rouen. After an ineffectual search for flint implements, I went 
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