Hood — On the Rotifer a of the County Mayo. 669 



Oe. rmicicola, Kellicott. Hudson and Gosse, supplement, p. 6. Western, 

 Journ. Quekett Club, (2) iv., p. 320, PI. xxi., 1, 1891. Plentiful 

 in spheres of Ghiotrichia piswn from the Knappagh lakes : 1889, 

 '91, '94. Mr. "Western found this species in Eichmond-park in 

 1890, its first recorded appearance in Britain. 



Oe. brevis, Hood, Journ. E. Microsc. Soc, 1893, p. 448, pi. vii. I 

 found a number of specimens of this species on Myriophyllum in a 

 small lake on the Knappagh road : 1889, '92, '94, It has also 

 been found in Germany by Bilfinger. Among the four species 

 of Oecistes enumerated as Irish by Miss Glascott is Oe. Irachi- 

 atus, Hudson, a form first found by ifle in 1882. We have 

 now, accordingly, ten species of this genus recorded from 

 Ireland. 



Lacinularia socialis, Ehrenb. Yery abundant on Chara and other 

 aquatic plants in the lakes of the Knappagh district. I have 

 already called attention to the absence of this species during the 

 earlier months of summer. It is remarkable that this very con- 

 spicuous species is absent from Miss Glascott' s list ; perhaps it is 

 rare in the east of Ireland. 



Conochilus volvox, Ehrenb. Abundant in marsh-pools among rushes, 

 2 miles S.E. of Westport : 1889, '92 ; near Castlebar, 1891. 



C. unicornis, Eousselet, Journ. Quekett Club, Jan. 1892. This rare 

 species is a lake-dweller. I found it both in 1892 and 1894 very 

 abundant in two lakes in the Knappagh district. The large and 

 beautiful spheres each contained from a dozen to over a hundred 

 individuals. 



Okdek II.— BDELLOIDEA. 

 Family Philodinid^. 



Philodina roseola, Ehrenb. A great many specimens in an old quarry 



near Westport, 1891, and in bog-pools, 1892. 

 P. erythrophthalma, Ehrenb. I found this widely- distributed species 



on weeds in a bog in 1891 ; also attached to the tubes of 



Fredericella sultana in a lake on the Knappagh road, 1891, '94. 

 P. citrina, Ehrenb, A few examples on Chara in a peat bog, E. of 



Westport, 1894. 

 P. tulerculata, Gosse. A number of examples of this rare species were 



got among decayed vegetable debris from the bottom of a lake two> 



miles east of Westport, 1891, '92, '94. 



