HYDRACARINA : THE GENUS EYLAIS LATR. 115 



The anterior pair of processes are shorter and directed rather 

 more towards the front. The posterior pair are stouter than in 

 the case of E. mulleri. The fringed margin of the mouth is not 

 quite circular, the anterior portion showing three blunt angles. 

 The anterior edge of the capitulum has a small piece cut out. A 

 small area close behind the mouth has a number of coarse pores. 

 The pharynx extends a little beyond the capitulum, and has some 

 resemblance to that of E. mulleri. 



E. undulosa attains a length of 2-7 mm. It is, so far as recorded, 

 not a widely distributed species, having only been recorded from 

 the Royal Canal near Dublin and from Russia and Germany. 

 The sex has not been determined and the life-history is unknown. 



Eylais unisinuata Croneberg. (PI. 3, fig. 5). 



1902. Croneberg. Bull. Soc. Nat. Moscow, p. 98, plate xii. 



fig. 9, Or-C. 



1903. Halbert. Ann. Mag. Nat. Hist., Ser. 7, vol. xii. pp. 

 511-512, fig. 7. 



Croneberg' s original description is somewhat meagre, but 

 Halbert has supplemented this from material taken in the River 

 Corrib near Galway, which he has referred to this species. From 

 the Russian description, we learn that the eye capsules are united 

 anteriorly by a narrow bridge, having a length equal to about half 

 that of the capsules. The anterior margin is almost straight be- 

 tween the anterior extremities of the capsules and has only an indis- 

 tinct notch in the middle ; on each side of the latter there is a short 

 bristle. Beneath the notch, and pointing anteriorly downwards 

 into the body, is a process for muscle attachment. The posterior 

 margin of the bridge is short and straight, and forms the base of a 

 deep bay, separating the posterior halves of the two capsules. The 

 Irish material appears to be very variable so far as the intercap- 

 sular bridge is concerned. The process for muscle attachment is 

 large and semicircular, and extends as far as or even beyond the 

 anterior margin of the plate. The inner and outer margins of the 

 capsules are decidedly sinuate. 



Croneberg describes the palpi as in some measure resembling 

 those of E. emarginata Piers. The bristles on the inner edge of the 

 second segment are not pectinate. The anterior inner surface of 

 the third segment is strongly developed and has numerous 



