198 MR. LUBBOCK ON SOME FRESHWATER ENTOMOSTRACA. 
the fourth segment, counting always from the base, has several more hairs than in 
Claus's figure. Besides the long seta at the middle of the segment, is another at the 
apex, which is quite as long, and had probably been accidentally broken off from Claus 
and Fischer's specimens. "The three terminal segments increase respectively in length, 
and decrease in breadth. In the centre of the apical segment, on the posterior side, is a 
small notch and a minute hair. The terminal setze are six in number, the central one 
being the longest. The penultimate setze are correctly figured by Claus, except that he 
makes them a little too short, the anterior penultimate being in my specimens as long 
as the apical segment—though upon this point Fischer agrees with Claus. I could see 
no trace of the ridge described as running along the three terminal segments. 
The antennæ of the second pair have, as usual, on the basal segment a long setose hair, 
which points backwards. The posterior margins of the two apical segments have a row 
of short hairs. "The antepenultimate has some short spines, and the basal segment à row 
of fine teeth. The apical hairs differ in length more than they do in Claus's figure. 
The figures given by Claus of the mouth-parts are very correct. 
'The postérior legs consist of a single segment terminated by three setze, which, how- 
ever, in my specimens, are by no means similar to one another, as they are represented 
in Claus's figure. On the contrary, the inner hair is flat, lanceolated, and provided with 
similar flat secondary setze at the side. The other two hairs are simple setze, the outer 
one being rather more than half as long as the other. 
The abdomen* is as described by Claus. 
The young, when one day old, is rounder than that of C. brevicornis ; the appendages 
also are shorter. The anterior pair is inserted so far back that only the apical segment 
projects beyond the margin of the body. 
It seemed to me that the anterior appendages had two equal terminal sete, that the 
penultimate segment had one seta at the apex and one in the middle, and the ante- 
penultimate one at the apex. This, also, agrees with the arrangement in C. brevicornis. 
In addition there were a few smaller hairs, none of which, however, appeared to me to 
be seated at the apex. : 
The large spine at the base of the second pair of appendages seemed to me to be single, 
but to give off one or two short and small hairs; in Claus's figure it is double; from 
which and from other indications I am inclined to think that the specimen figured by 
Claus was not in its first state. The second segment bears, as in Claus's figure, two short 
hairs. The lower branch is as in C. brevicornis. The larger branch consists of a large 
basal segment, followed by two or three imperfect divisions, and terminated by a longer 
narrower terminal segment. The basal segment has a small hair, the second and third 
have each a long seta, the fourth again has a short hair, and the apex has a long seta and 
a shorter hair. 
The third pair of appendages are formed on the same type as in C. brevicornis. The 
small branch bears three setze, the middle one of which is the largest, and the inner 
* While adhering to the views I have aiready expressed (Nat. Hist. Rev., vol. i. p. 29) as to the homologies of the 
so-called “ thorax” and “abdomen” in Crustacea, I use the words here in their usual sense, being reluctant to com" 
plicate our nomenclature by any peculiar system of my own. 
