ARCHER, ON PALMOGL@A MACROCOCCA. 113 
enter into the characters of the genus Spirotznia, as already 
known, would be alike unnecessary and beyond the purpose 
of this communication ; they are to be found set forth, as far 
as is known, by various writers. No reproductive process 
having been noticed in this genus, its position, indeed, remains 
unsettled; but there cannot be much doubt but that, when 
discovered, it will be found to be by conjugation. However, 
the before-indicated parietal, spirally wound band of endo- 
chrome abundantly separates the two forms mentioned, 
included in Palmoglea by Kiitzing, from the forms I have 
previously adverted to, and from those included in the fourth 
and fifth types presently to be alluded to. There may, in- 
deed, be some possibility that likewise the form called Pai- 
moglearupestris (Kiitz.), which is thus spoken of —“ ues 
cellulis ex substantia gonimica convoluta transverse hyalino- 
zonatis;” also P.lurida,thus described—‘“Substantia gonimica 
fascize-formi sub-convoluta,’ may belong here; but without 
seeing fresh specimens of the plants so named by Kiitzing, it 
would be impossible certainly to decide. Having thus elimi- 
nated Palmoglea Roemerzana, P. monococca, P. endospira, and 
P. closteridia, and possibly P. rupestris and P. lurida, the 
. remaining forms included in this genus by Kiitzivg probably 
belong to one or other of two further apparently naturally dis- 
tinguished generic types, and these, indeed, so far as I can see, 
are the only two alluded to by De Bary. These are— 
(4) Cylindrocystis (Menegh.), and— 
(5) Mesotenium (Nag.). 
Both these, as previously indicated, agree with the fore- 
going (P. Reomeriang excepted), as well as with each other, in 
the elongate and elliptic or oblong form of the cells, but they 
are distinguished from them and from each other by the struc- 
ture of the cell-contents. In Cylindrocystis the cells possess 
granular chlorophyll-green contents, and at the centre a paler 
or less dense region. This clear central space is described by 
De Bary, for C. Brébissonii, as rounded and four-cornered ; 
to me it appears of extremely indefinite outline, if, indeed, it 
can with propriety be said to possess a proper outline at all. 
Within this occurs a nucleus, but not always evidently. Be- 
yond it, at each side, occurs one, or, in longer cells, about to 
divide, occur two somewhat elongate, apparently dense bodies 
(starch-granules), from which radiate, in an irregular sub- 
stellate manner, the general granular cell-contents. The 
arrangement of the ctll-contents here reminds one very much 
of that in Zygnema. Reproduction is by conjugation, and 
evolution from the contents of the spore, in germination, of 
four young cells the same as the parent.* 
* De Bary, op. cit., p. 37, t. vii E., 18 — 22. 
