112 BRITISH ENTOMOSTRACA. 



POLYPHEMUS STAGNORUM, Leach, Diet. Sc. Nat., xiv, 540. 



Latreille, Cuv. Reg. An., iv, 165. 

 Desmarest, Cons. gen. Crust., 365, t. 54, 



f. 1. 

 POLYPHEMUS PEDICULUS, Straus, Me"m. Mus. d'Hist. Nat., v. 



M. Edwards, Hist. Nat. Crust., iii, 389. 



MONOCULUS POLYPHEMUS, Jurine, Hist. Nat. Monoc., 143, 1. 15, f. 1-3. 

 CEPHALOCULUS STAGNORUM, Lamarck, Hist. An. s. Vert., v, 131. 



Bosc, Man. d'Hist. Nat. Crust., ii, 247. 



LE MONOCLE 1 QUEUE RETROUSSEE, Geoffrey, Ins. Par., ii, 656, No. 2. 

 MONOCULUS OCULUS, Gmelin, Linn. Syst. Nat., edit. 13th, i, 2996, 



No. 10. 

 SCALICERUS PEDICULUS, Koch, Deutsch. Crust., h. xxxvii, t. 2. 



The body is oval-shaped, separated from the head by a 

 deep indentation. 



The upper part of the head is almost entirely occupied 

 with the eye, which is provided with its rotatory muscles, 

 as in the Daphniadae, and is beset, all round the upper and 

 outer edges, with numerous lucid areolae, about twenty in 

 number. The lower part is quite transparent, the black 

 mass filling only about three fourths of the whole. 



The mandibles are almost exactly the same as in the 

 Daphnia. 



The inferior antennae or rami (t. XVII, f. 1 ci] are large, 

 and divided each into two branches. The anterior branch 

 has three articulations : the first the largest ; the second 

 is the shortest ; and the third is the longest and the most 

 slender. The first joint has one seta, the second one also, 

 and the third has two from the side, at equal distances from 

 each other, and three from the apex. The posterior branch 

 has four articulations, one very short and three longer. The 

 second joint has one seta at its extremity ; the third has 

 one springing from the middle of the articulation, and one 

 from the extremity. The last joint has one seta on its 

 edge, and three at its extremity. The setae are jointed at 

 about half the length. 



The superior antennae are small, arising from the edge 

 of the head below the eye ; they are sharp-pointed, and 

 terminate in two or three fine seta-, directed upwards. 



