DAPHNIA. 97 
5. Daphnia reticulata. Tab. VII, fig. 5; Tab. XII, 
fig. 1 , male, and fig. 2, var. quadrangula . 
Monoculus reticclatus, Jurine , Hist. Nat. Monoc., IB 9, 1. 14, f. 3, 4. 
Daphnia reticulata, Desmarest , Cons. gen. Crust., 374. 
— M. Edwards , Hist. Nat. Crust., iii, 381. 
— Baird , Trans. Berw. Nat. Club, ii, 148 {not 
Ann. Mag. Nat. Hist.) 
Daphnia ventricosa (?), Koch, Deutsch. Crust., h. xxxv, t. 21. 
Daphnia quadrangula, Muller , Entomost., 90, t. 13, f. 4. 
— Latreille, Hist. Nat. Crust., iv, 227. 
Monoculus'quadrangula, Gmelin, Liim. Syst. Nat., 2999, No. 24. 
Monoculus qu adran gularis, Manuel, Enc.meth., vii, 723, No. 15. 
t. 265, f. 8-9. 
Monoculus quadrangulus, Fabricius, Ent. Syst., ii, 492. 
The shell or carapace in this species is of a rounded 
oval shape ; the dorsal edge being slightly round, and the 
anterior bulging out a little inferiorly. The surface is 
covered with a complete meshwork of small hexagonal 
cells • and the inferior extremity is provided with a short 
spine, a little turned backwards. 
The head is rather small, and has no beak. It is 
deeply sinuated at its junction with the body, rising 
rather erect from that with a projection, and terminating 
in a blunt, rounded extremity, nearly filled with the eye, 
which is large and areolar. The filaments of the inferior 
antennae are not plumose. The sixth segment of the body 
is furnished with two projections, and a rather long spur. 
Ova about four in number. The colour of the shell is 
slightly greenish. 
The ephippium in this species differs considerably from 
that of the pulesc. It is more rounded, white in the centre, 
with a large round ampulla, containing only one ovum 
(t. XII, f. 2). When the'animal has the ephippium on, it 
possesses a square appearance, and is then the Daphnia 
quadrangula of Muller. 
In the month of September 1846 I found many spe- 
cimens of the male of this species at Highgate and Batter- 
sea ; and since then I have again found them at Highgate. 
7 
