698 Proceedings of the Royal Irish Academy. 



L. socialis occurred in profusion on the stems and leaves of 

 water-lilies in Crighdough. Loch, famous as the habitat of Naias 

 flexilis. 



There is some doubt as to the proper name of the species I have 

 called Euchlanis sulversa, Brjce. In Hudson and Gosse's Monograph 

 Mr. Grosse described and figured ^ a rotifer to which he gave the name 

 of Biplois propatula, and which differed from the other members of the 

 Euchlanidae in having the dorsal plate of the carapace divided in the 

 middle by a longitudinal V-shaped cleft. The same rotifer was again 

 figured and described by Dr. "W. Barnett Bum^, who asserted that the 

 V-shaped line seen by Gosse was due to an infolding of the membrane 

 connecting the plates, and not to a cleft iu the dorsal plate ; and that 

 consequently the animal should be removed to the genus Euchlanis. 

 Very shortly thereafter Mr. David Bryce described, under the name of 

 Euchlanis sulversa?, a form which, while resembling very closely in. 

 most respects the animal figured by Gosse and Burn, differs very 

 markedly in having the ventral plate larger than the dorsal, and over- 

 lapping it considerably at the sides — an arrangement which is unique 

 among the Euchlanidse. Mr. Bryce believes his species to be identical 

 with Biplois propatula, assuming that Mr. Gosse " might possibly have 

 been deceived in his interpretation of such difficult characters," and 

 that, in short, Gosse had turned his Eotifer upside down. In my 

 Houndstone specimens, however, the shape and relations of the carapace 

 were clear and distinct when the animals were swimming, and it seems 

 hard to believe that an experienced naturalist like Mr. Gosse (as well 

 as Dr. Collins, who sent him the specimens and drew the figures) should 

 have mistaken the ventral for the dorsal surface. I found the dorsal 

 plate very distinctly concave from side to side, rather than "nearly flat, 

 but having a central longitudinal depression," as Mr. Bryce describes 

 it, and the toes, somewhat more slender than in liis figure, were gently 

 curved dorsally, instead of being nearly straight. In all other than 

 these unimportant respects my specimens agreed perfectly with Mr. 

 Bryce's description. 



1 H. and G., " Monograph," ii., p. 87, pi. xxiv. 2. 

 ^ " Science Gossip," xxvi., p. 35. 

 ^Ibid. pp. 77-79. 



