THE FKESH-WATER SPONGE. 
141 
Hist.” for February, 1868 : — I have been engaged, like others, 
for some time past, in endeavouring to clear up the doubt 
which prevails in the scientific community, in regard .to the 
nature of the sponge. The question has been, is it an animal, 
or is it a plant ? Bowerbank, the highest classificatory autho- 
rity upon this subject for a long term of years, held that it was 
an animal ; but his bases for this theory were such that they 
did not appear to offer a satisfactory means of finally deciding 
the dispute. The latter remark applies with equal force to the 
investigations of Lieberkiihn.” 
It only remains for me to add, with regard to these lower 
organisms, or created beings {ctista), as also the Desmidieae, 
some of the Infusoria, and Diatomese, and doubtful Algae, and 
other Protoctista, that, by including them all in a fourth, or 
Primigenal Kingdom,” it prevents the unnecessary trouble of 
contending about their supposed natures, and of uselessly trying 
to distinguish the Protozoa from the Protophyta. 
