Peridinium Cypripedium and Urocentrum Turbo. 3 
Ehrenberg, and in no way is dependent upon the affidavit of 
Claparéde 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 infusorian as 
described 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 with 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. Claparéde 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 ‘ Infusions- 
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 ea cathedrd, 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 Ehrenberg 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 Urocenirum, “ 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- 
1* 
