98 
BRITISH ENTOMOSTRACA. 
The antenna consists of a long, round body, formed of two 
joints (t. XII, f . 1 a) : the first, the smaller of the two ; the 
second, much larger, cylindrical, and furnished with a 
short seta on each side. This joint is terminated by a 
long, sharp spine, which, at about the half of its length, 
appears jointed. The first pair of feet (t. XII, f. 1 b) 
are exactly the same as in pulex. The shape of the shell 
differs considerably from that of the female, being more 
oval, less rounded on the dorsal edge, and having the 
anterior margin straighter. 
The head, also, is rather longer, and even more erect 
than in the female. 
Hah . — Ponds and ditches in the neighbourhood of 
London, Berwick, &c., and commonly met with during 
all the summer and autumnal months.— 
6. Daphnia rotunda. Tab. X, figs. 4, 4 <z; Tab. IX, 
fig. 6, jun. 
Daphnia rotunda, Straus , Mem. Mus. Hist. Nat., v, t. 29, f. 27, 28. 
— M. Edwards, Hist. Nat. Crust., iii, 381. 
— Baird, Trans. Berw. Nat. Club, ii, 118. 
Daphnia reticulata, Baird, Ann. Mag. Nat. Hist., i, 257, t. 9, f.ll. 
Daphnia quadrangula (?), Koch, Deutsch. Crust., h. xxxv, t. 19. 
Daphnia mucronata (P), Koch, 1. c., k. xxxv, t. 20. 
{Young) Daphnia angulosa (?), Koch, 1. c., h. xxxv, t. 22. 
The shell or carapace in this species is nearly quite 
round, and the inferior extremity is provided with a short, 
blunt spine, projecting backwards. 
The head is small, depressed, and notched a little 
above its junction with the body. 
The superior antennae are of moderate size, of a flattened 
shape, square at the tip, and sending off from its upper 
edge a short, square branch (t. X, f. 4 a), both branches 
being terminated by several short setae. The filaments 
of the large antennae are not plumose. The surface of the 
valves is densely reticulated, being covered with a regular 
