History of British Entomostraca. 327 



Description — Body and tail not distinctly separated from each 

 other ; composed of ten segments, first segment largest, last one, 

 terminating in two short lobes, from which issue two long filaments, 

 slightly serrated on their edges. At the junction of the fifth with 

 the fourth articulation, the body is very moveable, and the animal fre- 

 quently turns up the posterior extremity upon the anterior, in the 

 manner of the species of beetle called Staphylinus (Plate IX. Fig. 1.) 

 Jurine has taken the trivial name of Slaphylinus from this circum- 

 stance, objecting to the name of minutus by which Midler desig- 

 nates it, as he says it is possible we may find still smaller species. 

 I have, however, retained the name which Muller gave it, as he is 

 the first author who has given any lengthened description of it. The 

 males are smaller than the females — antennae, (Fig. 1, 2, a a) very 

 short compared with those of preceding species. In female (Fig. 3) 

 composed of nine articulations ; in male (Fig. 4.) only of seven. Be- 

 tween fourth and fifth articulation, in both sexes, we see a small 

 lateral ring, of one short articulation and three or four short setae. In 

 male both antennae have swelling and hinge-joint, the swelling exist- 

 ing chiefly about the fifth articulation, all the five first, however, 

 being of greater size than the corresponding ones in the female ; 

 hinge-joint near the extremity. Antennules* (Fig. 5.) composed of 

 two articulations : upon first articulation is placed a small shoot ter- 

 minated by four setae, second articulation furnished with seven short 

 spines on upper edge, and terminated by four longer ones. Jurine 

 makes the antennules consist of six articulations, and his figure of these 

 organs differs entirely from mine, Avhich, after frequent and repeat- 

 ed examinations, never varied in their appearance in the slightest. 

 Mandible (Fig. 6.) in figure /esembles very much the internal man- 

 dible of the quadricornis, the " barbillon" springing from the centre, 

 and consisting of three articulations, terminated by several setae. 

 The lips in this species are easily to be seen, and are provided also 

 with a " barbillon," which is a pretty large oval body (Fig. 70 di- 

 viding at extremity into four fingers of equal length, each furnished 

 with three setae. Hands (Fig. 8.) of more simple organization than 

 in the preceding species. They consist of three articulations, the 

 last of which appears to be a very fine hook, forming with the 

 other two, an angle always directed forwards towards the mouth. 

 These hooks appear to stop all molecules of food in their passage, 

 and by their constant motions carry them to the mandibles. Feet 

 (Fig. 9, 10,) much longer in proportion than in either of the preced- 

 ing species, and differing in some respects from each other. The 



* " Palpi" of Muller. 



