1916] ROE—SPLACHNIDIUM 401 
strikingly characteristic feature of Splachnidium. The material 
proved inadequate for the study of reproduction, but furnished a 
good series for the development and fate of the “‘apical cell.’’ No 
mitosis was observed, and hence no chromosome count was possible. 
It is hoped that some one in the region where Splachnidium grows 
may be interested enough to investigate material secured at the 
exact time when cell division occurs, probably at night, or to 
observe the behavior of the living bodies after discharge from the 
reproductive sac. 
Origin of the initial row 
The first feature which tends to set the initial cells apart from 
adjacent border tissue is the taking on of a heavy coat of mucilage 
(fig. 1). In this and subsequent early stages the heavy mucilage 
coat is the only character which distinguishes the initial from 
young vegetative hairs abundant in the apical region (figs. 2-5). 
A second feature marking this unique structure is the beginning 
of resorption of cross-walls and loss of original definite nuclear 
structure (figs. 4, 6, 13, 15). Gradually a complete linear row 
of cells, reaching entirely through the thallus, is differentiated from 
the surrounding tissue as an initial row (figs. 5, 7, 8, 13, 15). 
Sometimes there is no evident differentiation of tissue at an 
early stage, but portions of old apical hairs may assume the heavy 
mucilage coat (figs. 9-11), and there follows an involving of the 
entire linear row of which the hair is a terminal portion. Part 
of the old hair may be cast off, eventually leaving only the lower 
portion (fig. 11). 
By the time an entire linear row is so differentiated, the char- 
acteristic filiform appendage, which has been described (10) as 
“growing between the cells of the thallus toward the center of 
the branch,” begins to be evident (figs. 15, 16). Pressure of 
abutting tissue has narrowed the basal portion into a tail-like process 
as resorption of old walls and cell contents has gone on, whereas 
freedom from pressure above has allowed expansion into a pear- 
shaped oval. At this stage all of the original contents left in 
the filiform portion consist of granular patches of cytoplasm, and 
in the oval portion there is a similar granular substance with the 
