Terrestrial Form of Zygnema ( Zygogontum ) emcetorum . 137 
until in many cells, at the best, but a very narrow connecting bridge 
remains (cf. above). It would appear that as a general rule the segregation 
of the two chloroplasts is practically complete before a new septum arises. 
A comparison of the above with West and Starkey’s account (cf. also 
Fig. 1 with their Figs. 1 and 2 ) will show that the Hindhead form differs 
X T 
Fig. 1. a-H, cell-structure and cell-division in the Hindhead form of Zygnema ericetorum ; the 
drawings made from the living Alga. i-J, cells of the aquatic form, from Frensham ; the drawings 
made from preserved material. For description, see text. (All figures x 850.) 
fundamentally from the ordinary type in two respects, viz. in the more 
definite shape of the chloroplasts, and in the frequent presence of two of 
them in the mature cell. It may be held by some that the differences are 
sufficiently pronounced to warrant the establishment of a distinct species, 
but I am not prepared at present to take up this attitude (see also p. 148). 
It may well be that observation of forms, like that at Hindhead, is 
