DAPHNIA. 97 



5. DAPHNIA RETICULATA. Tab. VII, fig. 5; Tab. XII, 

 fig. 1, male, and fig. 2, var. guadrangida. 



MONOCULTJS RETICULATUS, Juriiw, Hist.Nat. Monoc.,139, t.14, f.3, 4. 

 DAPHNIA RETICTJLATA, 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, Mutter, Entomost., 90, t. 13, f. 4. 



Latreille, Hist. Nat. Crust., iv, 227. 



MONOCTJLUS'Q,UADRANGULA, Gmelin. Linn. Syst. Nat., 2999, No. 24. 

 MONOCULTJS QUADRANGULARIS, Manuel, Enc. meth., vii, 723, No. 15. 



t. 265, f. 8-9. 

 MONOCULUS QUADRANGULTJS, Fabricim, 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 ephippimn in this species differs considerably from 

 that of the puleoc. 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 



