D. KRYCE ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. 65' 



In 1905 James Murray (55) annoimced the discovery of the 

 curious Bdelloid, Microdlna jyaradoxa, for which he created the 

 new family Microdinadae. This and numerous other discoveries 

 of Bdelloid forms hitherto unknown, and in all cases communi- 

 cated to me before publication, led naturally to the discussion in 

 our correspondence of the demerits of the current classification of 

 the group. The arrangement of the genera and species now ad- 

 vanced is in great measure the outcome of that discussion. To 

 some extent the lines on which it is mainly framed have been 

 indicated by my correspondent in recent papers, notably ia (56) 

 *^The Bdelloid Rotifera of the Forth Area" (1905) and in (63) 

 " Phllodina imtcrostyla and its Allies " (1908). 



In the former of these he provisionally redefined the genera 

 Phllodina, CaUidhia, and Rotifer as follows : 



Philodina. Having four toes and a corona consisting mainly 

 of a pair of wheel-like ciliated discs. 



A . Eyes present ; oviparous. 



B. Eyes absent ; oviparous. 



0. Viviparous ; eyes present or absent. 



Callidtna. Having three toes or a perforate disc formed by 

 a union of the toes ; oviparous ; eyes present or absent. 



A. Food moulded into pellets. 



B. Toes bearing a number of cup-like suckers, or united 



to form a broad disc, 



C. Toes three ; distinct, food not moulded into pellets. 



ItOTTFER, Viviparous ; toes three. 



In the latter paper he discusses exclusively the genus Philodina^ 

 which he redefines as distinguished by : 



Four toes, eyes cervical or none ; 



and subdivides into five groups of species : 



I. Oviparous. 



II. Semiloricated. 



Ill, Parasitic, 



t IV. Short-spurred. 



V. Viviparous. 



Daring the period covered by the foregoing retrospect the- 

 number of species known to belong to the Bdelloid group has^ 

 very considerably increased. In Ehron berg's classification of 



