230 BRITISH ENTOMOSTRACA. 



sharp-pointed beak (t. XXVII, i.\g,f; f . 3 a, b) and has 

 near its junction with the first thoracic ring, on each side, 

 a short, curved, sharp spine. 



The eye is single, in tlie male fixed upon a short peduncle 

 (f. 1 (/), and projecting forwards and slightly downwards ; 

 in the female sessile, " It is of a beautiful dark-brown 

 colour, with a shade of purple ; a circular space at the 

 extremity is colourless, and sparkles brilliantly." * 



The thorax is elongated, and consists of six segments, 

 the last of which is narrower than the others, truncated, 

 and terminates on each side in a point. Antennae long, 

 about two thirds the length of the whole body. Tliey 

 are composed of numerous articulations, about twenty-five 

 in number, each provided with one or more short setae. 

 In the male the right antenna alone is provided with the 

 swelling and hinge-joint. The swollen part is particularly 

 large, and club-shaped, " and running up through the 

 centre of the swelhng may be seen a muscle, which goes 

 to be attached to the hinge-joint. "f 



The antennules (f. 1 a) consist of a single branch, 

 which is divided into three joints, the terminal joint 

 being broad, and furnished with several long setae. 

 The basal joint sends off from its internal side a small, 

 slender twig, which is provided at the extremity with three 

 or four setae. The labrum or lip is well developed, and 

 consists of a projecting semi-oval plate, and two lateral 

 lobes of considerable size. 



The mandible (f. 1 b) is in form of a strong plate, fur- 

 nished with five stout teeth on its internal extremity, and 

 having a rather large, palpiform branch from its upper 

 edge, divided into two smaller branches. Each of these 

 is formed of tAvo articulations, the terminal one giving off 

 at its extremity several long, plumose setae. The jaws 

 are only rudimentary organs. 



The foot-jaws are three pairs in number. The first 



* Goodsir, loc. cit., 339. " The peduncle of tlie eye is of a dark blue.' — 

 raterson, quoted bv Templetoii, loc. cit. 

 i- Tbid., il)id. " 



