280 CHAS. D. SOAR ON 



proximal half, and three in distal half, distal end with three 

 pectinate spines ; fifth segment, extensor surface with two short 

 spines and three on distal margin, the flexor surface has about 

 five spines ; sixth segment, more slender than any of the other 

 segments, flexor surface with three or four small spines, without 

 claws, but with a long, fine terminal bristle at the base of which 

 there are one or two very short hairs. 



The genital area lies for about half its length between the 

 fourth pair of epimera, at each end is a strong, curved chitinous 

 bridge for muscle attachments. There are two pairs of acetabula 

 on each side of the genital cleft, protected by a porate valve 

 or flap which is probably fringed with short hairs. The acetabula 

 are oval or elliptical in outline, each pair being united by means 

 of a chitinous band ; the proximal and distal margins are rounded 

 and the ends pointing inwards, tapered. This number of 

 acetabula in the genital area is rather uncommon, the more 

 usual number being three on each side of the cleft. Sex un- 

 known. 



I wish here to acknowledge my indebtedness to Mr. William 

 Williamson, F.R.S.E., for his valuable assistance in determining 

 the characters of this water-mite. 



Towards the end of May in the year 1914, I received from 

 Mr. J. Wilson, F.R.M.S., a small collection of water-mites taken 

 in the neighbourhood of Staines. Amongst them were four 

 specimens of the same species referable to the genus Eylais, but 

 the name of which I was unable to determine. The most impor- 

 tant characteristic for purposes of identification in the species 

 of this genus is the eye area. This I was quite unable to obtain 

 a good view of while the mite was alive, so I killed the four 

 specimens and left them in the glycerine solution sufficiently 

 long to remove the colour from the integument. When this 

 was nearly complete, I was then able to see the eye-capsule quite 

 distinctly and was surprised not to find any actual plate or 

 connection between the eyes, a feature which is found, so far as 

 the literature at present available shows, in all other known species 

 of this genus, now numbering over a hundred. I dissected the 

 area surrounding the eyes and made a camera drawing of 

 this in the case of three of the specimens ; the fourth specimen 



