SPONGES Si 
In 1842 we find Johnston still uncertain as where to 
place sponges. After giving a series of arguments, derived 
from his own observations and those of others, this author 
says, “There is, however, nothing to forbid us believing 
with the earliest naturalists, that the sponges may belong 
to neither kingdom; nay, the very discussion leads to the 
conjecture that they do actually constitute a middle race. 
in whose features we can sometimes trace a predominance, 
now of animal and now of the vegetable nature. Few, on 
examining the Spongilla would hesitate to pronounce it a 
vegetable, a conclusion which the exacter observations of 
the naturalist seems to have proved correct; and when 
we pass on from it to an examination of the calcareous and 
silicous genera, the impression 1s not so much weakened 
but that we can say with Professor Owen, ‘thatif a line 
could be drawn between the animal and vegetable king- 
doms, the sponges should be placed upon the vegetable 
side of that line.’ We shall possibly, however, arrive at 
an opposite conclusion if, proceeding in our inquiry, we 
follow the silicious species, insensibly gliding on the one 
