Rhabdonia tenera , J . Ag. 
4i5 
Fusion with the Auxiliary Cell. 
The conjugating- tube, which proceeds from the trichophore, 
appears in all cases to unite with the auxiliary cell near its 
base (Figs. 12 and 14); at the point of union the conjugating- 
tube is more or less swollen and closely pressed against the 
auxiliary cell. The wall between them is absorbed, and 
the contents of the conjugating-tube unite with those of the 
auxiliary cell (Fig. 14). 
The number of auxiliary cells is very small compared with 
the number of procarps, not over two per cent. ; consequently 
they are quite certain to be found by some of the numerous 
conj ugating-tubes. 
Segmentation of the Carpogenic Cell. 
After conjugation the auxiliary cell cuts off a segment by 
an oblique wall near the top and on its inner side (Fig. 3). 
The cell thus cut off divides and gives rise to a mass of com- 
paratively small cells densely filled with protoplasm (Figs. 4 
and 5). By growth and repeated division the mass enlarges 
and finally completely surrounds the auxiliary cell, and also 
the three large cells which are borne upon it (Fig. 1). It is 
then possible to see that the whole mass is made up of 
radiating filaments of cells, the gonimoblastic filaments, which 
branch in a somewhat irregular manner, and at the ends bear 
short branched filaments of small cells, densely filled with 
protoplasm, which become spores (Fig. 1). Thus there arises 
an irregularly spherical mass of cells composed of gonimo- 
blastic filaments radiating in all directions from the carpogenic 
cell (Fig. 1. cpg) and bearing spores at the surface of the 
mass, the interior of which (the ‘ placenta ’) is composed of 
sterile cells which have enlarged considerably and lost most 
of their contents, with the exception of a delicate film of 
protoplasm lining the cell-wall. Imbedded in this mass are 
the three cells which were mentioned before as being borne 
on the auxiliary cell, and which are now very large and 
almost entirely destitute of protoplasm. 
