DAPHNIA. 91 



MONOCULTJS, Bradley, Phil. Account of Works of Nat., 202, t. 25, f. 5. 

 Le Puceron verd.'VTKe, Ledermuller, Mikroskop. Gemiiths. Augcn- 

 ergotz., 146, t. 75, f. 2. 

 Var. a. Daphnia longispina, Milller, Entomost., 88, t. 12, f. 8-10. 



— Latreille, 1. c, iv, 226. 



— Bosc, 1. c, ii, 283. 



— Ramdohr, Beyt. zur Naturg. eiu. Deutsch. 



Monoc. arten, 21', t. 7. 



— Lamarck, 1. c, v. 127. 



— Straus, 1. c, t. 29, f. 23-1. 



— Desmarest, 1. c. 872. 



— M. Edwards, 1. c, iii, 380. 



— Koch, Deutsch. Crust., h. xxxv, t. 17. 

 MoNOCULUS LOMGISPINUS, Fabricius, Ent. Syst., ii, 492. 



— Mamel, 1. c, 718, t. 265, f. 5-7. 



— Be Geer, 1. c, vii, 442, t. 27, f. 1-4. 



— Schaffer, Die griiu. Ai-ni-Polyp., 59, t. 2, f.l . 



Var. /3. Daphnia magna, Straus, 1. c, t. 29, f. 21-2. 



— Desmarest, 1. c, 373. 



— M. Edwards, 1. c, iii, 380. 



The shell or carapace is oval, quite transparent in 

 general, and very finely striated on the anterior and 

 middle portions of the valves, the striae crossing and inter- 

 lacing \\\i\\ each other. Sometimes it is of a red colour. 

 The lower extremity of the valves terminates in a sharp 

 spine, which is serrated on its edges. This spine varies 

 in length ; in general, in the adult, being short and 

 straight ; in some it is a prolongation of the dorsal 

 margin, in others it is directly in the centre, but in the 

 young, and in var. a, it is long, and slightly bent back- 

 wards. The head is large, rounded on the upper and 

 anterior portion, and produced lower down into a sharp, 

 pointed beak. The superior antennaR are exceedingly 

 small, consisting of only a slight protuberance, and five 

 or six short setae. The inferior antennae are very large. 

 The anterior branch consists of four articulations, the first 

 of wdiich is very short. From the extremity of the third, 

 issues a long filament ; and from the apex of the fourth, 

 three others arise, of equal length. The posterior branch 



