2 
LoBB^ on Micrasterias Benticulata. 
This is followed by the incision of the central and basal 
lobes^ and the central lobes being considerably larger than 
the basal the whole assumes somewhat the appearance of 
being composed of seven lobes. (See fig. 5.) 
After this a further incision of the central and basal lobes 
takes place (see fig. 6); then the sinuation of the end lobes_, 
and the denticulation of the whole completes the division (see 
fig. 7) ; then separation follows. 
In each stage the endochrome increases, but never extends 
throughout ; the hyaline portion becomes less, the frustule 
is gradually filled, and when self-division is completed, there 
still remains a perfectly hyaline portion all round the cell. 
The figure in Mr. Ralfs^s work represents the first 
exudation from the parent frustules as very large, and 
filled with a light colouring matter of the same density 
throughout, leaving no portion hyaline. There is no divi- 
sion into lobes, no incision, no denticulation, no granular 
endochrome ; and all these are so natural, and so perfectly in 
keeping with the parent frustules, that I do feel justified in 
differing even from so high an authority, and am compelled to 
say, that if ever such a self-division was witnessed, it must 
have been an abnormal one. Having seen many frustules in 
the course of self-division, and on different occasions, I 
can with confidence assert, that I have never seen any devia- 
tion from the method now described : there is a slight varia- 
tion in the spreading of the endochrome, which, it should 
be observed, is always granular. 
The self-division only requires to be witnessed, to show 
that what I have stated is correct; and, should any one 
observe the phenomenon from its commencement to its close, 
as I have done, he will, with me, assert that a more beautiful 
object can hardly be seen even by a microscopist. 
There was one object which struck me very forcibly, on 
looking over the gatherings from Epping Forest, and which I 
have endeavoured to figure, magnified only seventy-five dia- 
meters. It differs, in several respects, from Actinophrys sol, 
though there is some resemblance, both in its circular figure 
and in the rays that issue from the disc; the central disc 
is perfectly hyaline, excepting the cell-walls, the cells of 
the inner disc being larger than the cells (if I may so 
term them) of the outer disc. It may, or it may not, be 
new, but I have never seen it figured. 
