786 
Thomas. — Notes on Cephaleuros. 
connexion precludes this interpretation. On the other hand, the close 
connexion, in several cases, between the Alga and certain pale filaments 
which may be traced outside the Alga, seems to indicate that the hyphae, 
which in some way have become closely connected with the discs, are 
of a Fungal nature. 
A large number of tests were tried to demonstrate the nature of 
the cell-wall in this organism. Insolubility in cupric ammonia and in 
various acids, together with coloration tests, showed that the cell- walls did 
not consist of pure cellulose. 
Tests were made for other substances, and among them, those described 
by van Wisselingh (17) for chitin were tried, in particular those tests by 
which chitin was converted into mycosin by means of dilute potash. The 
presence of the latter substance, which microchemical ly responds in a very 
definite way, was shown by staining in various reagents. Schultz’s solution 
stains the walls of the Alga, in particular the transverse walls, a deep 
blue-violet. 
It is evident from these tests that the constitution of the cell membrane 
of this Alga approximates to that of the cell- walls of certain Fungi. 
The striations, referred to above, when observed in surface view, appear, 
in a middle focus, as an oblique fringe to the cell-wall, but in the lowest 
focus they are seen as straight or slightly curved markings across the cell 
lumina. The appearance of obliquity is due to the marked concavity 
of the lower cell-wall of the Alga nearest the leaf. 
At first it was thought that the appearance was due to a crinkling 
of the cell-wall owing to contraction in spirit, but this does not explain the 
fact that it is only in the cell-wall adjoining the host that the crinkling or 
striations are observed. 
That the appearance was not due to markings on the cell-wall of 
the epidermis of the leaf was evident from the way in which the striations 
corresponded with the cell lumina of the Alga, and also from the fact that 
they were clearly demonstrable in detached pieces of thalli which were not 
separated from the leaf by means of knife or razor. 
It was thought that the appearances might be due to the contraction 
or hypertrophy of a membrane. One suggestion is that the membrane in 
question is the cuticle of the leaf dragged away by, and still adherent 
to the Alga, but from sections and from an examination of the lower surface 
of the thallus, it is clear that the striated appearance is in some membrane 
between the Fungal hyphae and the Alga, that is, in the Algal cell-wall 
itself. 
The appearance is perhaps to be explained as the result of a lamellose 
structure of the cell-wall of the Alga, similar to that of Trentepohlia , 
as described by West and Hood (16). It is singular, however, that the 
markings should be confined to the lower wall of the Alga. It is not 
