D. BRYCE OX A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. 6 



o 



use of the number of spurs and of toes on the foot. It has been 

 pointed out by Murray in a recent paper (63) that the dis- 

 tinction made was inaccurate as between Eotifer and Actinurus, 

 since the foot is not thrice furcate in the species assigned to 

 Piolifer. But if inaccurate in that case, the phrase " cauda ter 

 f urcata " is correct with regard to the genus Philodina, and 

 clearly indicates the two spurs, the two dorsal toes, and the 

 two terminal toes possessed by all but one of the species w^hich 

 were described by Ehrenberg as members of that genus. 



In 1884 Hudson (17) recognised the distinctive character of 

 the manner of creeping peculiar to the group, and proposed 

 that the several genera should form a separate order, that of 

 the Bdelloida, or Leech-like Creepers, and this proposal was 

 further established by its adoption in The Rotifera, published 

 by him in 1886 in collaboration with Gosse (19). In this work 

 the new family Adinetadae and the new genus Adineta were 

 created for the reception of a species which differed markedly 

 in the type of the corona from all others of the group included 

 hy them at that time. The four recognisable genera of Ehren- 

 berg were placed in the new family Philodinadae, and were 

 distinguished as before by the presence and position of the eyes. 



Earlier in the same year, 188G, the importance given by 

 Ehrenberg to the eyes in the generic distinction of the Philodinaea 

 had been challenged by Milne (18), who proposed to ariange 

 the various species into genera either new or redefined, and to 

 discard altogether all generic characters relatinof in anv wav 

 to the eyes. He claimed for his scheme that it did not dis- 

 sociate manifestly similar forms, at least as regards some nineteen 

 species examined by him. His most valuable suggestion in this 

 paper was that the genus Philodina should be distinguished by 

 the possession of four toes, thus giving first place to the character 

 which Ehrenberg had indicated in 1830 in the phrase "cauda 

 ter furcata." 



In 1888 Milne (23) adduced fresh instances in support of his 

 previous contention, and proposed further that the genus Rotifer 

 should be distinguished b}' the character " viviparous." 



Another important advance was made in 1889, when Plato 

 (27) pointed out that the Bdelloida shared with the Seisonidae 

 the peculiarity of having two ovaries, whereas all other Eotifera 

 have one only. He proposed therefore to di\ide the class Eotifera 



