A REVISION OF THE ROTATORIAN GENERA LEPADELLA 

 AND LOPHOCHARIS WITH DESCRIPTIONS OF FIVE NEW 

 SPECIES. 



By Harry K. Harrtng, 



Custodian of Rotatoria, United States National Museum. 



INTRODUCTION. 



In the following pages an attempt has been made at a revision 

 of the Rotatoria that have been gradually accumulating under the 

 generic name Metopidia. A.dequate descriptions exist only in the 

 case of a few strikingly marked species, and the majority are decidedly 

 miobtrusive in appearance, so that the group is now in a very 

 confused condition. This is not entirely of recent origin, but dates 

 back in part at least to Ehrenberg. He seems to have been tem- 

 porarily under the ascendancy of Schelling's Naturphilosophie 

 and the circular, quinarian and other vagaries of Oken, who was 

 trying by abstract speculation to discover the simple and perfectly 

 logical system pervading aU nature; the facts, when found, were 

 bound to fit the theory. This influence is very evident in the highly 

 artificial classification proposed by Ehrenberg in his paper read 

 before the Berlin Academy in 1850. 



While Ehrenberg gradually drifted away from this system, he 

 never rescued the LepadeUids, the one group that, more than any 

 other, had suffered from it. We find, therefore, in his Infusions- 

 thierchen of 1838 a total of four species belonging to this genus 

 under seven specific names, one animal being allotted no less than 

 four specific and three generic names, fomided on the supposed 

 number of eyespots; none, two or four. That all the LepadeUids 

 have two eyespots, and two only, was demonstrated long ago, and 

 it is in no case accepted as a generic character. Dujardin, in 1841, 

 imited these supposed species in one genus, Lepadella, and attempted 

 to reduce their number, but his first-hand knowledge of the animals 

 appears to have been rather limited and his work is probably in this 

 instance simply compilation. Gosse, in The Rotifera, followed his 

 example and left the species in a single genus, applying to it the 

 name Metopidia, the most recent one of those proposed up to that 

 time. His treatment of the different species is a great improvement 



Proceedings U. S. National Museum, Vol. 51— No. 2164. 



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