Dr. W. Baird on new species of Entomostracous Crustacea, 283 



same size as the anterior, but swollen and sloping downwards to 

 an obtuse point. Centre of carapace swollen. The surface of 

 the valves is hispid all over with short stiff setse, which beset 

 the edges round the whole circumference. When rubbed off, 

 they leave the appearance of little pits or depressions. 



Pediform antennae provided with a pencil of rather long plu- 

 mose filaments. 



The colour of the shell is of a very light olive-greenish hue. 

 The ova appear shining through the carapace like two orange 

 spots. 



Hab» Pool of Gihon, Jerusalem. Mus. Brit. 



Diaptomus similis, PI. VI. fig. 3. 



In the general form of the body, the number of articulations, 

 &c., it agrees with D. Castor. The head, however, is curved 

 downwards into a short curved beak. The antennae are furnished 

 on the upper edge with short setse at each joint; but these setae 

 are set at right angles with the joint, and are nearly alternately 

 short and long, the longer ones being nearly double the length 

 of the shorter ones. The third pair of foot-jaws have the same 

 number of articulations as those of D. Castor, but the setae at the 

 terminating joints are much shorter and slightly aculeate. The 

 fifth pair of feet in the male have the last articulation of the 

 right branch terminated by a long and strong hook, which is 

 much longer than that of D. Castor, The swollen hinge-joint of 

 the right antenna of the male, when under the lens, is finely 

 striated. 



Hab, Pool of Gihon, Jerusalem. Mus, Brit. 



EXPLANATION OF PLATES. 

 Plate V. 



Fig. I. Estheria Gihoni, nat. size: 1 a, magnified; ib, portion of cara- 

 pace, magnified ; 1 c, terminating hooks of abdomen ; 1 d, pre- 

 hensile feet of male. 



Fiff. 2. Daphnia Atkinsoni, magnified, side view : 2 a, Ditto, prone j 2 c, 

 portion of carapace highly magnified, to show the structure, 



Plate VL 



Fig. 1. Cypris celtica, magnified: la, b, Ditto, in different positions; 

 1 c, portion of carapace, highly magnified to show the structure ; 



1 d, lucid spots ; 1 e, pediform antennec. 



Fig. 2. Cypris orientalis, magnified : 2 a, b, Ditto, in difierent positions ; 



2 c, lucid spots ; 2 d, structure of carapace ; 2 e, pediform an- 

 tennaj. 



Fig. 3. Diaptomus similis, magnified : 3 a, terminating setse of tail. 



