Dr. Philippi on a neiu genus of Entomostraca. 303 



e. The pair of simple legs. 



/. The vulva. 

 Fig. 10. The male in the act of coitus hanging to the tail of the female, mag- 

 nified with the same power. 



g. The posterior antennae ? 



h. The two penes. 

 Fig. 11. A female of Hersilia apodiformis. Natural size. 



11. Peltidium purpureum, a new genus of Entomostraca. 



Plate IV. fig. 12 and 13. 



I have only one specimen of this little animal, which is 

 scarcely ~" in size. The body is expanded in a shield of seven 

 segments, which in its general contour is ovate. The first 

 segment is nearly as large as the following segments together, 

 and has in some degree the form of a trapezium whose base is 

 turned backwards, and is bounded by a concave line. Ante- 

 riorly it has a truncated protuberance, on which two small 

 round points appear, and probably are the eyes. The following 

 five segments are of a narrow crescent form ; the last and small- 

 est is again in the form of a trapezium. Behind this projects 

 the very short two-pointed tail; each of its points is furnished 

 with four bristles, of which the inner one is the longest. The 

 antennae are two in number ; they proceed from the angles 

 which the first segment forms with its appendage, attain nearly 

 a third part of the length of the animal, and consist of six 

 short articulations, the two last of which are very small. On 

 the front side, and especially at the apex, they are provided 

 with long bristles. I find six pairs of legs. The first pair, 

 which appear to be inserted after the first segment, is simple, 

 and seems to consist of three articulations only. (Fig. 13, c.) 

 The second articulation, somewhat thickened at its base, has 

 a tooth towards the end of the hinder side ; the third articu- 

 lation is a narrow moderately curved claw. The following 

 four pairs of feet are biramified, and have this character in 

 common, that the hinder or inner branch originates at a mo- 

 derate distance from the apex of the stalk. (See fig. 13. d, e,f.) 

 Both the outer and inner branches of the second pair have two 

 articulations, and the first branch is twice as long as the second. 

 Its second articulation is the longest, and ends with three 

 short bristles, two of which are bent in the form of a hook, (d.) 

 The third pair (e.) is distinguished from the two following 



