430 Hi. James- Clark—The American Spongilla. 
than that, owing to the extreme transparency of the cells, and 
their consequent inconspicuousness, That the cytoblastema, 
notwithstanding its low undeveloped state, is the true contractile 
. . 
it 1s barely possible to discover even the trace of a cell on the 
collection of coarser granules than are generally diffused through 
the cytoblastemic layer. The irregular and jagged outline, and 
the caudate projections of the cells (2*) also tend to tempt one 
to the latter view. The cell element in this case, then, corres- 
ponds only to what is usually considered the cell contents, and 
anucleus. The contents are composed of coarse and fine grey 
quently are so transparent and slightly refractive as to appear, 
collectively, unless specially focussed upon, as a faint blotch in 
such a function, we could detect no change other than might be 
produced by the varying length and breadth of the cell, and the 
Tale, Last By pug ovetiving each other in Spongila alba. At 
