382 Fritsch, Observations on the young; plants of Stigeoclonium Kütz. 
with a higher objective, turn out to be the chloroplasts in the ceils 
of the endophyte. With the change in colour and arrangement of 
the chlorophyll a thickening of the cell-walls goes hand in hand. 
The cells of the Uladophora in most cases appear quite healthy 
and still retain their rich green contents; in a few cases, however, 
the contents had lost colour, though I am not prepared to attribute 
this to the action of the endophyte. These latter cases admitted of 
a better examination of the endophyte, and most of my figures were 
made from such specimens. 
The form, I have just described, comes near to Zntocladia 
(Endoderma) gracilıs of Hansgirg (88c, p. 499). This Alga, grow- 
ine on Cladophora fracta Wahl var. gossypina (Kütz.) Rabh., 
is either endo-or epiphytic. It consists of creeping, branched fila- 
ments, which frequently become united to form a parenchymatous 
stratum or & compact mass of irregular shape. "The chloroplast is 
at first parietal, whereas later on it only occupies a part of the cell- 
wall; this latter remains thin. However the cells of Ent. gracilıs 
Hansg. are cylindrical, 2—3.5 u, only rarely 4 w in diameter, whereas 
they are 2—3 times as long. In this respect they differ very con- 
siderably from those of my form, in which the cells are usually ai- 
most isodiametric (Tab. XIL, fig. 35) their diameter being 20—30 «; 
where the individual filaments can still be distinguished, the cells 
are occasionally seen to be somewhat oblong (Tab. XII, Fig. 36), al- 
though their diameter considerably exceeds that of the cells n Hans- 
girg’s Species. 
In the Endoderma leptochaete, described by Huber (92#, p. 320) 
he remarks that „L’epaisseur des cellules vegstetfVes est tres vari- 
able (de 5 & 15 w), de m&me leur longueur. Dans les filaments 
allonges elles sont generalement plus longues que larges, tandis que 
dans les filaments formant un thalle compact elles sont plus ou moins 
renfl&es ou presque spheriques (Pl. XV, fig. 2).“ At the same place 
another species, Zndoderma Jadinianum Huber, is described (loc. 
eit. p. 322); I extract the following from the description: „Les 
cellules sont larges de 10 & 20 „, rarement de 20 a 30 w generale- 
ment plusieurs fois plus longues que larges. Le chromatophore a la 
forme d’une plaque parietale a bord generalement peu decoupe et 
occupant la face dorsale de la cellule. ..... Par suite d’une rami- 
fieation abondante ou quand plusieurs thalles se rencontrent, il se 
forme ungecoussiner ecelulaner 2.0. 25 = khertie= 12 one 
15 of Huber, (exhibiting the „coussinet cellulaire“), shows consider- 
able resemblance to what I frequently found in my form. However 
both the species of Zndoderma last discussed were found to develop 
delicate, unseptate hairs, when cultivated for some time (cp. Huber 
92®B, p. 320 and 323), and although Ihave had my form under in- 
vestigation for some weeks, I have observed nothing of the kind. 
Lemmermann (95, p. 31), who found an Alga, which he believed 
to be possibly identical with the Znd. Jadinianum of Huber, also 
mentions nothing concerning hairs. Bi 
Although I consider it possible that the species of Endoderma, 
I have described above, may correspond to Z. Jadinianum Huber, 
I am at present not in a position to affirm this with certainty. I 
hope, that continued observation of this curious form will settie all 
