ARCHER, ON PALMOGL@A MACROCOCCA. 123 
macrococca) equivalent to M. Braunii (De Bary) ; but if the 
figures given by Rabenhorst be compared with those of M. 
Braunii given by De Bary, it will be seen that the former 
represent a broadly elliptic, the latter a cylindrical, form. 
Indeed, I consider that Rabenhorst’s figures said to repre- 
sent “ P. macrococca”’ seem actually to be copied from De 
Bary’s figures of M. violascens. As to Rabenhorst’s descrip- 
tion of ‘ P. macrococca,”’ an objection to be made to it seems 
to be that it is not sufficiently in detail, as the characters 
given would as well apply to two or three apparently distinct 
species; nor do the characters agree with the figures (seeing 
that they represent violascens). And as to the validity of 
their distinctions, I would beg observers to suspend their 
judgment, at least until careful examination be made of the 
fresh specimens. In regard to the generic characters given 
by Rabenhorst for Palmogleea, they are intended to include 
only, and to be restricted to, the forms appertaining to Meso- 
tenium (Nag.), while Cylindrocystis (Menegh.) is included 
in Penium (Bréb.). But, as I have before pointed out, Cylin- 
drocystis seems sufficiently well characterised as a distinct 
genus. The statement as to the constant incorporation of 
cell-wall and -contents in the act of conjugation must be modi- 
fied as regards Mesotenium, as will be seen by the descrip- 
tion in this paper. 
Of the three species of Mesotzenium described by De Bary, 
I have above indicated that I believe the P. macrococca 
could not have heen Mesotenium Braunit (De Bary). The 
narrow-cylindrical cells with rounded ends seem quite to 
separate it from the broadly elliptic form, gradually diminish- 
ing towards both ends, of M. violascens (De Bary). 
I believe, then, it is more probable with M. chlamydos- 
porum (De Bary) of properly described species, that the 
identity of P. macrococca exists. 
It is indeed to be regretted that in endeavouring to settle 
the identity of the plant in question, from the insufliciency 
of Kiitzing’s description, we have little else to go upon but 
the external outline; yet the genus being known, I must 
hold to the opinion that this is by no means unimportant, 
and there can be no doubt but that the genus here is Meso- 
tenium. After some search in our Dublin and Wicklow 
hills, I have succeeded in finding, and pretty certainly iden- 
tifying by De Bary’s description, his three species of that 
genus; and in my opinion M,. chlamydosporum is the only 
one which suits Kiitzing’s (indeed but vague) description of 
the debated plant. They are both cylindrical, with rounded 
ends, and coincide pretty nearly in the measurements, and 
