the Cystocarp in Rhodomelctceae. 303 
pericentral cell is the auxiliary cell ; if with the sporogenous 
cell, after it has been cut off, then that cell is the auxiliary cell, 
as is contended by Schmitz. In default of this evidence there 
is, however, this difficulty in regarding the derivative cell as 
the auxiliary cell, that it is not cut off when fertilization does 
not take place ; and if it be separated in consequence of 
fertilization, but before conjugation with the carpogonium, 
it is necessary to assume the transference of the effect of 
fertilization in some indirect manner, which, while it is not 
inconceivable, is still an unnecessary assumption, in this case. 
For division of the auxiliary cell into a sporogenous portion 
and a sterile portion is found by Schmitz to take place in 
Callithamnion , and the same statement is made for the car- 
pogonium itself in Nemalion ninltifidum. 
Method . 
The method which I have found most convenient for 
observations on procarps is that which has been recommended 
by several others, viz. prolonged treatment with strong 
glycerine after staining, preferably with Hoffmann’s blue. No 
stain is required in many cases. This treatment causes the 
transparent cell-wall to swell greatly, and the interior of the 
procarp is observed through the gaps between the opaque 
cell-contents. While this method does not involve any 
change in the relative positions of cells, it must be remem- 
bered that all the figures accompanying this paper are drawn 
by means of the camera lucida from preparations in which 
the cells are much farther apart than they are in nature. 
The outlines of the cells are the limits of the opaque contents. 
The pit-connexions characteristic of the Florideae are an 
invaluable indication of the genetic relationship of the cells. 
