62 ON A RARE BRITISH ENTOMOSTRACON. 



It is vei-y remarkable that my own experience of the niimerical 

 scarcity of this species has been similar to that of all previous observers 

 except Kurz. Thus Fischer says he could find only one ; Leydig also 

 found only one ; Norman found three, and subsequently one more; and 

 in the present case only two were found. This scarcity of numbers is 

 perhaps more apparent than real, as the animal is evidently a mud- 

 lover, and we have all searched for it in the water instead of on the 

 surface of the mud. Kurz, the only one who found it in any quantities, 

 obtained it free from mud by the following ingenious contrivance : — 

 A small net fastened in the ordinary way to a metal ring, and fixed 

 to the end of a long string by several strands, has attached to its lower 

 edge a large stone, and to its upper edge a piece of cork. This is flung 

 into the water as far as the string allows and sinks to the bottom, 

 where it stands on its edge owing to the stone and cork attached to it. 

 As it is dragged along the stone stirs up the mud in front of it, and all 

 the lighter particles, including entomostraca and most living organisms 

 are swilled into the net. In this way Kurz succeeded in capturing 

 many females of the species and a few males, the only ones ever 

 captured. This need excite no surprise, as even in the commonest 

 Daphniadro males are always very rare. 



The following is a description of my specimen, which is a young 

 female, drawn on Plate I., Fig. 1 : — 



The shape of the valves of the carapace is oval, and they are very 

 convex, so that the thickness of the body when viewed edgeways 

 is so gi-eat as to make it appear almost spheroidal. Their surface 

 is reticulated all over wdth polygonal, mostly hexagonal markings, 

 which are not shown in the figure. Length from top of head 

 to bottom of carapace 1-80", breadth 1-100". Colour brick 

 red. The head is bounded by a gentle curve behind, abruptly 

 truncate in front. There are two eyes, one compound (m) near the apex 

 of the head, and one smaller simple e3'e(«) below it. Theantennules (/,)are 

 tolerably large, and spring from the forehead just below the small eye. 

 The antennae (/) are very large and fleshy and divided into two branches, 

 the upper one four-jointed, v.'ith three long sets and a short spine on 

 the terminal joint ; the lower one three-jointed, the first two joints 

 each with one seta, the terminal joint like that of the other branch. 

 None of these seta are plumose. The base of each antenna also bears 

 two spines. Perhaps the most marked feature of the animal is the 

 bristles with which the edges of the carapace valves are fringed. These 

 are set in an unbroken I'ow from just below the mandibles to the 

 junction of the valves behind. They are flexible, rather stiff, and 

 branched hut not plumosi', var\-iug in length from about 1-500" along 

 the front of the body to about half that size along the posterior edge. 

 The abdomen bears as usual one pair of mandibles, (a,) five pairs of 

 branchial limbs. {/;. 1 — 5,) and a very large post-abdomen (r/) terminating in 

 two long rather straight hooks. This part of the body is larger than in 

 auv other species of the family with which I am acquainted, and is 



