506 W. WILLIAMSON AND C. D. SOAR ON BRITISH HYDRACARINA : 



The legs are rather more slender than in L. insignis, and this 

 may be attributed to the fact that the fourth, fifth and sixth 

 segments of the second, third and fourth pairs of legs are 

 decidedly longer. The fifth segment of the second pair of legs 

 has swimming hairs, the length of which about equals that of 

 the segment itself. 



The inner posterior ends of the second pair of epimera just in 

 front of the genital valves are decidedly thickened, and are about 

 twice as broad as in L. insignis. The fourth pair of epimera is 

 nearly of equal width throughout, any tendency to increase 

 manifesting itself towards the inner end, where the posterior 

 corner is broadly rounded off. 



The genital area extends for about one-third of its length 

 outside the bay formed by the fourth pair of epimera. The 

 thick chitinous ridge which forms the posterior boundary of the 

 area lies close in and extends a little way up the sides. The 

 third pair of acetabula is very little shorter than the other two 

 pairs. A few hairs may be noted along the posterior margins 

 of the valves. 



Lebertia glabra Sig Thor. 

 (Sub-gen. Pseudolebertia.) 



1897. Lebertia glabra Sig Thor, Arch. Math. Naturmd., xx. (3), 



19, pi. iii. fig. 23. 

 1907. Sig Thor, Zool. Am., xxxi. 105-115, figs. 73-81. 



Lebertia glabra appears at present to be limited to Norway 

 and Scotland. It belongs to the smaller species, and appears to 

 vary from about 0'6 mm. to 1*1 mm. in length, and about 

 0'5 mm. to 1*0 mm. in breadth. In outline, the body presents 

 a somewhat rounded appearance, and, viewed from the side, the 

 venter is seen to be much less arched than the dorsum. The 

 dorsal surface is of a brownish -yellow colour with dark-brown 

 patches, and is rendered conspicuous by the pale-yellow T-shaped 

 figure of the excretory organ showing through. The ventral 

 surface and the legs have a tinge of green in their colouring. 

 The skin is covered with short chitinous ridges, some of which 

 may even be forked. On the dorsal surface these are quite short 

 and lie more or less parallel to the long axis of the body. On 

 the ventral surface they are longer and run transversely. In 



