178 Nellie Carter. 
the individual is usually, though not invariably, attached at one 
corner. 
Eichler and Gutwinski (’94) figured some time ago a new alga 
under the name of Sycidion polonicum, which shows some super¬ 
ficial resemblances to these abnormal forms of Characiopsis saccata, 
but there are one or two differences between the alga described by 
the above authors and the one under consideration, which make it 
rather unlikely that the two are identical. In the first place the 
one figured by Eichler and Gutwinski is somewhat larger than the 
triangular forms observed here, and again their description of the 
cell-wall would scarcely apply. In Sycidion polonicum there is a 
thick cell-wall which increases in thickness at the upper angles 
of the cell, whilst in Characiopsis saccata the cell-wall is always 
very thin and delicate, in the triangular forms as well as in the 
more elongated cells, and there is never any visible increase in 
thickness at the angles. 
Another epiphyte of very peculiar form was figured by 
Braun (’55) under the name of Characium horizontale, which is 
rather suggestive of some of the irregularly shaped specimens of 
Characiopsis saccata, cf. Fig. 2, D. Since only one of these 
peculiar individuals was observed by Braun, and it occurred 
amongst other allied species, including Characium longipes 
[=Characiopsis longipes (Rab.) BorziJ, Characium clavatum, Cli. 
ornithocephalum and Ch, obtusum , it would seem highly probable 
that this particular individual was simply an abnormal specimen of 
one of these other species, and does not represent a distinct 
species at all. Braun himself seems to have considered this possi¬ 
bility and to have come to the conclusion that the form of this 
individual was too peculiar for it to have been merely an 
abnormal specimen of Ch. ornithocephalum , but in view of the wide 
variability of form which has been observed in the collection from 
Sutton Park, it seems quite probable that the individual called Ch. 
horizontale by Braun really was simply an abnormal specimen of 
one or other of the species amongst which it was living. 1 
These two examples, Sycidion polonicum Eichl. and Gutw. 
and Characium horizontale A. Br. are merely mentioned as 
showing some similarities to the unusual forms often observed 
amongst individuals of Characiopsis saccata, but as has already 
been shown, it is most unlikely that either of these is identical 
1 This idea is supported by Dr. E. Lemmermann in Algologische 
Beitriige. Xli, Die Gattung Characiopsis Borzi, Abh. Nat, Ver. Brem. Bd. 
XXiil, H. 1, 1914. Lemmermann only' includes Characium horizontale A. Br. 
in Characiopsis as a doubtful species. 
