72 D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. 



distinguished from each other by the arrangement of the foot- 

 glands, which in Discopus are placed in transverse series, but in 

 Anomopus in longitudinal series as in all other Bdelloida. 

 For the moss-dwelling species I propose the new genus Mniobia, 

 distinguishing it from Discopus by the longitudinal arrange- 

 ment of the foot-glands, and from the long- footed Anomopus by 

 the relatively short foot. 



The order in which these families and genera should be 

 placed is more than difficult to determine. If, as I think is 

 the case, the pellet-making species are nearest to the primitive 

 Bdelloid type, the genera Habrotrocha, Scepanotrocha, and 

 Ceratotrocha may be taken as representing the central line of 

 growth from which at one period or another other groups have 

 branched off, in most cases to subdivide again. If, however, the 

 functional development of the various genera that is to say, their 

 capacities for gathering food, for locomotion, their general activity 

 and endurance be considered, then I think the genus Philodina 

 should stand first, yet be closely approached by Rotifer and 

 Callidina, while at the foot of the list should appear Microdina 

 and Bradyscela, with Ceratotrocha but little above them. 



But it is impossible in the mere sequence of genera and species 

 to give any adequate idea of both the relationships and the 

 comparative development of the several groups which the genera 

 are intended to represent. For the sequence of genera which 

 after various rearrangements I have finally adopted I make 

 no claim save that of convenience. 



The new genus Scepanotrocha is represented only by two 

 species new to science, and descriptions of these accompanied 

 by figures follow after the general classification. 



The list of species regarded as insufficiently described or 

 otherwise invalid is supplemented by remarks on certain of 

 the species included therein. 



I conclude this paper with a list of works dealing with earlier 

 classifications of the Bdelloida, or containing original or supple- 

 mentary descriptions of species, so far as I am acquainted with 

 them. Throughout the text reference is made to these works 

 by numbers enclosed in brackets after the author's name. 



(In the event of any described species or work having been 

 omitted from the respective lists I shall be grateful if the 

 fact be made known to me.) 



