204. MR. LUBBOCK ON SOME FRESHWATER ENTOMOSTRACA. 
The two terminal segments have undergone no material alteration. 
The second pair of antenne closely resembles the figure given by Liljeborg (l. c. pl. 13. 
fig. 7); but the second segment of the branch “a” has four setze, and the apex of the 
basal segment of the branch “b” has a row of small spines on the inner side. 
The mandibular palpus is also well figured by Liljeborg (/. c. pl. 13. fig. 10); but the 
terminal segment of the larger branch has seven large setee in addition to the smaller 
one, which does not in reality form part of the series. The mandibular teeth are nine in 
number. 
The anterior maxilla is also well figured by Liljeborg, but the plate “a” had in my 
specimen seven large hairs, besides the small one. 
The second pair of mazxille offers no special peculiarity. 
The mazillipeds consist of seven segments. The basal one has ten strong setze, the 
second five, the third three, the fourth and fifth two each, the sixth two (one on each 
side), and, finally, the seventh four. 
The anterior pair of legs also are correctly figured by Liljeborg ; but in my specimens 
the setz were longer in proportion to the legs themselves. The outer branch has three, 
the inner only two segments. In the other legs both branches consist of three segments. 
The fifth pair of legs can easily be distinguished from that of the other species. 
Like the other pairs, they consist of a two-jointed basal portion and two branches. In 
the female (Pl. XXXI. fig. 4a) the inner branch is two-jointed, and is either cylindrical 
or club-shaped, according to the aspect from which it is regarded. It has two or three 
rudimentary spines near the apex. The outer branch (Pl. XXXI. fig. 40) is also two- 
jointed. The basal segment is rather longer than broad; the terminal segment is short, 
and ends in two great and two small spines. In the male they are quite unsymmetrical, 
one being more than twice as long as the other. Both of them, however, consist of the 
usual parts—namely, a basal two-jointed portion bearing at the apex two branches. The 
basal portion is in this case normal, and but slightly unsymmetrical. In the longer leg 
the inner branch is reduced to a simple cylindrical appendage (Pl. XXXI. fig. 34). The 
outer branch (Pl. XXXI. fig. 3) consists of two segments: the basal is cylindrical, and 
bears a strong spine on the middle of its outer side; the terminal segment is in the form 
of a long, narrow, sickle-shaped spine. 
The shorter leg (Pl. XXXI. fig. 3 c) has a small one-jointed inner branch. The outer 
branch is also small, and bears a setose spine, which probably represents the terminal 
segment. 
The abdomen in the female is three-jointed, and the basal segment has a spine on each 
side. The lamelle are not longer than the last segment, and bear six plumose setae, of 
which the five outermost are very stout. The inner borders of the lamellz also are 
plumose. The abdomen of the’male consists of five subequal segments. The inner seta 
is more than half as long as the others, but much narrower and not plumose. Near the 
base is a portion (Pl. XXXI. fig. 6 a) distinguished by the walls being suddenly and 
conspicuously thinner than elsewhere. At first I looked on this as an accidental varia- 
tion, but I have since found the same structure in all the specimens I have examined, 
not only of this species but of D. castor. 
