Miscellaneous. 315 
alternate leaflets, which are only found on the apical flower ; but in 
their place in the other there are sometimes three bractez, placed 
far from each other on the peduncle, the larger one (which alone is 
constantly found) being placed at the base, where it springs from 
the scape. The flower opens regularly from the bottom upwards till 
within a few of the top; then the top one opens, and after that the 
remaining ones which surround its base. 
RIVER-SPONGE INSECT. 
‘Correction of a mistake relating to the River-Sponge Insect, and to 
the Freshwater Sponge. By John Hogg, Esq., M.A., F.R.S., 
F.L.S., &c. 
To the Editors of the Annals and Magazine of Natural History. 
GrENnTLEMEN,—Having forgotten to correct an error into which 
the able Entomologist, who contributed the description of the ano- 
malous Insect discovered by myself inhabiting the Spongilla fluviatilis, 
to the ‘ Magazine of Natural History,’ had inadvertently fallen, in 
making me conclude that the motions of that Insect were mistaken 
by some French naturalists for the movements of the Freshwater 
Sponge itself, and having lately read the same error inserted in the 
« Annales des Sciences Naturelles,’ I think it incumbent on me no 
longer to delay sending you the following correction, which I hope 
you will favour me with publishing in an early Number of your ‘ An- 
nals and Magazine of Natural History.’ 
The mistake, which I here point out, is contained in this para- 
graph, taken from p. 200 of the ‘ Magazine of Natural History,’ 
vol. ili. New Series ;—‘‘ Mr. Hogg, F.L.5., by whom these insects 
were discovered, during a series of minute investigations upon the 
Spongilla, has arrived. at the conclusion that the motions of these in- 
sects, and the undulations which they produce in the water, have 
been mistaken by Laurenti and others for movements of the Sponge 
itself, and which they have accordingly regarded as affording proofs 
of the animality of that substance.” 
Again, I find the same translated into p. 380 of the ‘ Annales des 
Sciences Naturelles,’ Séconde Série, tom. xi. Zoologie, in the fol- 
lowing words :—‘‘ M. Hogg, qui a découvert ces insectes pendant 
une série d’observations délicates, qu'il avait entreprises sur la Spon- 
gille, est arrivé 4 conclure que ce sont les mouvemens de ces insectes 
et les ondulations qu’ils produisent dans les eaux, qui ont été pris 
par Laurenti et autres pour les mouvemens de la Spongille elle- 
méme, et regardées comme des preuves de l’animalité de cette sub- 
stance.” 
Now, as well from this paragraph, as from its translation, it must 
not only be inferred, that the same remarkable insects were actually 
present in those specimens of the Spongilla, whilst M. Laurent and 
others were witnessing the movements described by them, and that 
they had not noticed the insects themselves; but also, that the un- 
dulations in the water or currents were produced by the respiratory 
motions of these identical insects alone, and of no other parasitical 
