Peridinium Cypripedium and Urocentruni Tui-bo. 3 



Ehrenberg, and iu no way is dependent upon the affidavit of 

 Claparede and Lachmann. The latter can lay no greater claim 

 to correctness than Mr. Carter in this respect; and all are equally 

 liable to a misapprehension of the nature of the infnsorian as 

 descrijjed by Ehrenberg. The fact that the authors of the 

 * Etudes' found the animal in question, as they think, in Berlin, 

 as it were under the very eyes of Ehrenberg, renders the identi- 

 fication no more certain than the discovery of the same by Mr, 

 Carter, as he thinks, far off in England. 



I cannot help deprecating the confidence Vith which Mr. 

 Carter pronounces upon what he calls my mistake, seeing that 

 his judgment is based upon a description at second-hand, as I 

 infer from his quotation of Ehrenberg's statements from the 

 ' Micrographic Dictionary.' The basis for an identification is 

 meagre enough in the work of the Berlin micrographer; and 

 how much less satisfactory in the Dictionary of Griffith and 

 Henfrey, every one knows who has compared the two books. 

 Messrs. Claparede and Lachmann frequently find occasion to 

 deplore the unsatisfactory character of the descriptions and 

 figures of Ehrenberg ; but if they never had cause to complain 

 before, it must have occurred when they attempted to decipher 

 the illustrations of Urocentrum on plate 24 of the ' Infusious- 

 thierchen.' For my own part, I felt the same restraint when 

 originally working up my article; and Mr. Carter must pardon^ 

 me therefore when I say that I cannot see the necessity or 

 the proper basis for his ex cathedra, even though he may 

 swear upon the original work itself. I am, however, far from 

 attributing to your distinguished authority upon the group of 

 Protozoa the singular fancy, possessed by some, for deciphering 

 the obscure two- line descriptions of the old-time species-makers; 

 still less would I suppose him capable of that remarkable mania 

 for identifying such zoological vagaries as those of Rafinesque 

 with this or that animal simply because it came from the same 

 locality as that named by that singular enthusiast. 



Since, however, Mr. Carter has so positively pronounced upon 

 this matter, I am compelled to assume the figures and descrip- 

 tion of Ehrenbei-g to stand in the place of the animal itself, and 

 not what others may happen to think it ought to be. Ehren- 

 berg says, in his generic diagnosis of Urocentrum, " corpore non 

 ciliato, fronte ciliis coronata." Now in Peridinium Cypripedium 

 all of the body (excepting the broader end, which is occupied 

 by the pseudo- cuirass) is covered with cilia, and there is no such 

 thing as a corona of cilia upon it. The anterior and posterior 

 transverse annular furrows seem to be bands of vibrating cilia 

 simply because these cilia are only rather more crowded along 

 the edges of the furrows than elsewhere. The mouth of Uro-. 



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