THE 
MONTHLY MICROSCOPICAL JOURNAL. 
OCTOBER 1, 1875. 
I . — On Cephalosiphon and a New Infusorion. 
By Dr. C. T. Hudson, LL.D. 
( Taken as read before the Royal Microscopical Society.) 
Plate CXVII. 
Nature is certainly feminine, for she is the most capricious of 
deities ; now refusing the slightest favour to her ardent worshipper, 
and then, when he has lost heart and is about to give up the pur- 
suit, overwhelming him with a lavish kindness that is almost as 
embarrassing as it is tardy. For years I had hunted in every 
brook, pond, and ditch, within some miles of my house, and always 
with the hope that some day among my other captures I should 
light on Cephalosiphon and Ptygura ; two rotifers that I had 
never seen, and which, so far as they had been described, stood 
sadly in the way of what seemed to be a tolerably satisfactory way 
of classifying the Rotifera. So at last I determined to accept pro- 
visionally some suggestions that had been made about these two 
doubtful species, and to consider that Ptygura Melicerta and Cepha- 
losi'phon Limnias had no right to their rank, but that the former 
was the immature condition and the latter a temporary state of 
some other species. 
When I had struck out their names from the list of rotifers, my 
classifying went gaily on ; and as I had got rid of two of my chief 
stumbling-blocks I soon finished my scheme to my own satisfaction. 
It was now Dame Nature’s turn. I had given up all hope of 
winning her favour and of finding the creatures, and I had resolved 
to do without both it and them ; I had made (as I thought) a 
perfectly satisfactory classification in spite of her ; I had played my 
best card and it remained for her to trump it ; which she promptly 
did, proving to me in a trice that perfect classification is often but 
another name for imperfect knowledge ; for on my going to Nailsea 
ponds (an old haunt of mine) to get something fresh for my micro- 
scope, on the very first weed I plucked were Cephalosiphon and 
Ptygura, both on the same leaf ; and a short inspection gave me an 
uneasy suspicion that the latter was probably a mature form, and 
that the former was a permanent one ; .so that my knot was not to 
be cut by the simple method of striking their names out of the list 
of rotifers. 
It seems a paradoxical thing to say that ignorance makes classi- 
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