302 
Birge—Notes on Cladocera. 
Bunops,* gen. nov. 
Plate XIII. Fig. 1. 
The head is very small and extends anteriorly much as in 
Drepanothrix. The forehead is flattened, somewhat kite¬ 
shaped as seen from the front, and has a nearly -hemispherical 
elevation in the center behind which lies the eye. The valves 
are nearly round, compressed, crested on the dorsal margin, 
and extend posteriorly into a blunt semicircular projection, 
Ventrally the valves gape in front and about the middle of the 
ventral margin are folded in toward each other. This infolding 
continues to the posterior end of the margin. Its effect is to 
enable the posterior part of the valves to touch each other and 
so close the branchial cavity behind. The free edge of the 
valves is fringed in front with long, slender, straggling hairs, 
while posteriorly they are short and closely set. At the pos¬ 
terior portion of the shell these hairs are apparently above the 
margin, owing to the fact that the infolded portion of the valve 
extends dorsally as well as toward the median line. The shell 
bears hexagonal reticulations, more distinct on the head and 
in the ventral part of the valves. 
The post-abdomen is broad, compressed and rounded as seen 
from the side. It is divided by a notch into a pre-anal and a 
post-anal portion. The posterior, dorsal, margin of the pre-anal 
part is convex and armed off the edge with 6-7 small recurved 
teeth and on the sides with 2-3 rows of fine hairs. There is a 
small but well marked abdominal process. The anal region 
bears 2-3 small teeth on each side. The caudal claws are 
curved, stout and denticulate and situated on a small conical 
terminal projection. 
The antennules are long, slender and cylindrical, bearing an 
anterior sense-hair, two pairs of posterior sense-hairs, and ter¬ 
minal sense-hairs which number about 11 and are of equal length. 
The antenna is of moderate length, slender and rather weak. 
The setae are 3000-311. The basal seta is the longest but is 
* fiovvo}, elevation and coif}, eye. 
