130 
OTTO C. GLASER 
The prospective cnidophages undergo striking changes which 
emphasize still more the disparity in size between them and the 
interstitial cells. The young cnidophage enlarges, partly by the 
development of great vacuoles in the cytoplasm, (fig. 8), and 
partl}^ because the cell contents withdraw from all except certain 
portions of their boundary, remaining connected with it only 
here and there by strands. 
When the differentiation of the cnidophage is complete, it 
presents the appearance shown in fig. 9. Each cell has a recep- 
tive eminence in which the cytoplasm remains naked and in the 
Fig. 8 Showing young cnidophages with blunt pseudopodia. Also interstitial 
cells. 
embryonic condition. From this point pseudopodia may be sent 
out, but in appendages in which ingestion has taken place, only 
short, blunt processes are found. 
After the cnidophage has ingested its fill of nettles, degenera- 
tive metamorphosis sets in. This process is characterized chiefly 
by retrograde changes in the nucleus, which gradually looses all 
visible differentiation, and becomes irregularly lobed or stellate 
(fig. 6). As the finished cnidocyst show^s no histological details 
other than the nematocysts and their enclosing membrane, the 
inference that nucleus and cytoplasm both degenerate completely 
seems well founded. 
The complete history of the cnidocyst remains in doubt. 
. Grosvenor was not able to determine with certaint}^ where the 
bounding membrane comes from, nor have my own efforts to 
