THE GENUS LEBERTIA. 493 



plate on the outer border and then continues as a filiform exten- 

 sion coming well up towards the first pair. The third pair is 

 triangular with its suture extending inwards for about three- 

 fourths of the distance to the genital area. The fourth pair is 

 also three-sided, the outer side being not straight, but curving 

 well round to the inner posterior corner. The epimera are 

 perforated by numerous pores which are visible externally as 

 groups of fine pores. 



The legs all have the first three segments short and the la.st 

 three long, and in addition it will be noted that the terminal 

 segments are rather thicker towards the distal extremity. The 

 first segment of all pairs of legs has three or four short spines on 

 the extensor surface ; in the case of the second and third pairs of 

 legs, one of these is longer, flattened and bipectinate ; in the 

 fourth pair of legs the segment is much larger than in the others. 

 The second and third segments apparently have some latitude in 

 their equipment of spines, but the distal ends have one or two of 

 these flattened bipectinate spines. The fourth segment of the 

 third pair of legs has one swimming hair, and the fifth segment 

 has three. The fourth segment of the fourth pair of legs re- 

 sembles that of the third pair, while the fifth segment has 

 two or three swimming hairs. The claws have a short thin 

 lamina. 



The genital organ is pyriform in outline, the narrowed anterior 

 end being united to the epimera by a subcutaneous chitinous 

 strip. Posteriorly, the genital area extends for about one-third 

 of its length beyond the epimera and is bounded by an arc-shaped 

 chitinous ridge. The anterior sclerite is short and thick. The 

 two anterior pairs of acetabula are roughly rectangular, with 

 rounded corners, and are about twice as long as broad. The 

 posterior pair are more nearly round. The porose covering valves 

 have four or five large hair ports along their outer edge, and along 

 the inner edge there is a larger number of fine pores, which varies 

 with the sex, numbering in the female about twelve pairs and in 

 the male about twenty. The anal orifice lies about midway 

 between the genital area and posterior body margin. 



L. jimbriata has been taken in Surrey and Suffolk. Halbert's 

 fimbriata of the Clare Island Survey has been redescribed as 

 L. celtica Sig Thor. 



