134 
IS THE FEESH-WATER SPONGE {SPONGILLA) AN 
ANIMAL ? 
Br JOHN HOGG, M.A., F.E.S., F.L.S., &c. 
I HAVE lately read Professor W. C. Williamson’s paper on 
that curious but very puzzling natural production, the 
Sjpongilla jiuviatilis, in the last number (26) of the Popular 
Science Review, with much pleasure. 
The author says, very correctly, in common with its spongy 
relatives, its claim to rank amongst animals has been exten- 
sively questioned,” — although recent examinations of the 
marine sponges, aided by microscopes of high power, and 
modem perfection, have detected in the minute structure of 
some of the species a similarity, or affinity, in certain organic 
properties, rather to an animal, than to a vegetable, being. 
Still, admitting such an increase in our knowledge of these 
remarkable organisms — in the absence of any decided and 
generally received proof of animality — I am uncertain of the 
correctness of that view. Thirty years ago, I maintained the 
probability of certain marine sponges (Spongice) being of the 
nature of lower animals, whilst the Spongillce and certain 
kinds of sea sponge, partook much more of a vegetable struc- 
ture. 
Even at this day. some distinguished naturalists retain the 
like opinion ; and of these, I will only mention two, viz. Pro- 
fessor Agassiz and the venerable Professor Ehrenberg. The 
modern views of the last microscopist and acute examiner of 
the lowest infusorial beings, during the extent of a very long 
life, still lead to the conclusion of sponges possessing more of a 
vegetable than of an animal nature. In proof of this, I will 
refer readers to a translation of his paper, on the “Animal or 
Vegetable Nature of Sponges,” 1866, published in the “Annals 
and Mag. Nat. Hist.,” for June, 1867. 
Ehrenberg there confirms my previously expressed opinion, 
that “ the sponges themselves are without those decisive cha- 
racters of independent animal bodies, which have been detected 
down to the smallest monads.” And also that “ the essential 
