BELONGING TO DAPHNIA AND OTHER ALLIED GENERA. 235 



Daphnia galeata, G.O. Sars, (Fig. C and PI. IX., figs. 10-17). 

 1863. Daphnia galeata, Gr. 0. Sars, Zoologisk Eeise i Som- 



meren, 1862, p. 21. 

 1867. ,, ,, P. E. Miiller, Danmarks Cladocera, 



(Naturhist. Tidskrift. III.), p. 117, pi. I., fig. 6. 

 The characters which distinguish this species from D. Kahl- 

 hergensis are noticed further on : in other respects a descrip- 

 tion of the one form may very well he applied to hoth. It 



may further be stated that the pig- 

 ment spots which are so conspicuously 

 developed in the antennal setss of D. 

 longispina are also present in D. Kahl- 

 hergensis and I), galeata, though not 

 so distinctly, their position being 

 sometimes indicated only by a thin 

 Fig. 0. transverse line. The size of 7). ya^ea^a 



Daplmia galeata, Sars, x 20. ^.^^^-^^ ^ -^ ^-j^^^j according to local- 



Different forms of head in speci- _ _ _ 



mens from Locli Yennaehar, ity, the following being the length 



arranged in order of age. measurements of fully gTown speci- 



mens from English, Scottish and Irish stations: Windermere, 

 2"1 millimetres; Loch Oich, Inverness-shire, 3 mm.; Lough 

 Erne, 1'9 mm. The Loch Oich examples are gigantic compared 

 v/ith others ; they are also more deeply coloured and have the 

 bulging at the base of the posterior spine which is seen also in 

 D. longispina, but not elsewhere, so far as I know, either in 

 I), galeata or D. Kahlhergensis. 



Daphnia galeata occurs in vast numbers in most of- the lakes 

 of Great Britain and Ireland, both at the surface and in the 

 greatest depths, but is usually most abundant at a considerable 

 distance below the surfarce. Though first described by Prof. G. 

 0. Sars from Norwegian specimens, and more recently by P. E. 

 Miiller in Denmark, it does not appear to have been found else- 

 where on the Continent of Europe, the form found in Bohemia by 

 Hellich, and called by him galeata, being probably referable to 

 D. Jardhiii. Neither does it seem to have been recognized in 

 America. Herri ck, in his " Entomostraca of Minnesota," gives 

 galeata as a synonym of hyalina, but his figures evidently have 

 nothing to do with the species now under consideration. 



