1 903 . K ANK . — Irish Fresh - wa ter En toni osti-a ca. 211 



Oughter and L. Arrow, only a few of the other important 

 sheets of water have been superficially examined — such as 

 I^. Melvin (by Dr. Creighton), L- Mask and L- Gill (by my- 

 self). Of the contents of the Mullingar lakes nothing is 

 known, nor of the wide expanses of lakes in lycitrim through 

 which the sluggish Upper Shannon winds, nor the Donegal 

 ly. Derg, nor the fine lake of the same name below Athlone ; 

 L- Conn, also, and Killarney are similarly untried. For 

 the future, however, students of fresh water Cladocera will 

 have the vast advantage of the great work on this group 

 lately published by Lilljeborg, "Cladocera Sueciae," which 

 seems to include all the British genera and species as well as 

 others not yet noticed in these islands. The classification in 

 some degree has been remodelled, and the authority of so 

 learned a master will, doubtless, compel the adoption of his 

 nomenclature and grouping. Hitherto there has been con- 

 siderable difficulty in identifying the two species of Dia- 

 pha?ioso?na—usLme\y, brachyurum and Ieuchte?ibe7'gia7i2t7?i—^3.r\ly 

 in consequence of the confused synonym}^, the names bra?id- 

 tianum and brachyiuiun having been applied it would seem to 

 both species in turn b}^ different authors, and partly on 

 account of some of the characters given by Sars not proving 

 constant ; for instance, the shape of the head, and also the 

 curvature of the spines on the abdominal claws. It is, there- 

 fore, highly satisfactory to find that the name brachyurum is 

 for the future definitely attached to the species with pro- 

 portionally shorter swimming antennae, which in IctcchtcTt- 

 bergiammi extend up to or be\'ond the hind margin of the 

 shell valves. Both exist in Irish waters. And, I am pleased 

 to be able to announce Holopediuvi oibbe7wn as Irish, having 

 taken this interesting animal when visiting Connemara in 

 company with Canon Norman in 1901. The important 

 family oi Daph7i2dcEh.a.s been reduced to more definite groups 

 of genera, and the extreme confusion that hitherto existed 

 in regard to the helmeted forms, seems satisfactorily disposed 

 of — characters having been found which enable the genera 

 and species to be definitely distinguished from one another. 

 Thus, it is satisfactory to find that the presence or absence of 

 the second eye-spot is no longer the main diagnostic between 



