380 Mr. Hodd's Observations on the Spongilla fluviatilis, 
Here, then, it will be apparent to every one how completely analogous the 
locomotive germlike bodies of certain kinds of Sea Sponge are to those of the 
River Sponge, and to the moving sporules of the club-shaped Ectosperma, 
but with this exception, viz. that the first bodies are said to be endowed with 
vibratory cilia. Nevertheless, I much desire that these bodies of the different 
Marine Sponges, of which only a few species have been described by Pro- 
fessor Grant, were again subjected to a more thorough and careful investiga- 
tion, in order to establish with greater certainty the presence and nature of 
their supposed cilia or cilialike appendages. Because, until a more intense 
power of the microscope be brought to the examination of these bodies than I 
can learn from the papers already referred to in the Edinburgh Philosophical 
Journal*, to have been at that time used, I cannot hold it to be by any means 
decided whether those currents there detailed be caused by real cilia or not. 
And I am bound to state this as my opinion, yet with all due respect and 
deference to the able observations of Professor Grant, inasmuch as I have 
myself been nearly misled in regarding the currents issuing from the sides of 
the locomotive sporules of the River Sponge, as being the vibrations of tufts 
of cilia, as I have before mentioned, in consequence of using a microscope 
made about thirty years ago, and one of an inferior power; and had I not 
been so fortunate as to have just had the opportunity of resubmitting some of 
those same bodies to a more modern instrument of a considerably higher 
power, I should unquestionably have declared that those sporules were fur- 
nished with true cilia, and that the currents noticed by me were produced by 
the vibratory motions of such cilia : whereas, in fact, their supposed cilia have 
at length turned out to be merely papillæ. 
Wherefore, having thus escaped from an unavoidable error, I feel the neces- 
sity of urging the re-examination of the locomotive germlike bodies of the Sea 
brane: these buds, when viewed in the microscope, were rather hollow in the centre, from whence 
a shoot pushed forth." The germination also of the sporules of the River Sponge as observed by me 
and described in a preceding page, is remarkably similar. 
* Dr. Grant appears to have used a 
: (polypi in the Sponge) 
à Vide Edinb. New Phil. Journ. for 1827, 
t ^ ‘ 
within the last twelve years. | great improvements that have been made in microscopes 
