114 
This species is not included in Batters’ List of the 
British Marine Algae published in the ‘‘ Journal of Botany ”’ 
in 1902, and we have not been able to find any record of 
its occurrence in British waters in subsequent literature ; 
we therefore regard it as an addition to the British flora. 
12. Colaconema reticulatum, Batt. 
Particularly beautiful specimens provisionally referred 
to this genus were found growing as endophytes in the cell 
walls of species of Cladophora at Port Erin. The species 
was first described by Batters in the “‘ Journal of Botany,” 
Vol. XXXIV, 1896, p. 8. The specimens which Batters 
describes were found in the cell-wall of Desmarestia Dresnay1. 
In his description Batters refers to the establishment of a 
filament with a double row of cells as being due to the 
limited space between the cells of the host plant in which 
the endophyte was growing. In the specimen collected 
at Port Erin on Cladophora, the same feature of a double, 
treble or even four-rowed main filament is clearly shewn, 
though in this case the plant has had ample room for 
expansion. The tendency to produce a multicellular 
central axis is therefore specific to the plant and not a 
condition imposed by the restrictions of the environment. 
13. Acrochaetium (Chantransia) endozoicum, Darb. 
The limitations of the genera Acrochaetium, Rhodo- 
chorton and Chantransia are by no means Clearly defined 
in the literature. Useful information may be found in 
a paper by K. M. Drew “ A Revision of the gequq 
Acrochaetium,’ Univ. of California. Pubk. in? Ber 
Volk XIV, No.5: 
Acrochaetium endozoicum was described by Professor 
Darbishire in the ‘“‘ Ber. der deutsch. bot. Gesell,” 1899, 
and included by Professor Rosenvinge in Part I of the 
“Marine Algae of Denmark.’’ Neither of the two authors 
give any information about the chromatophore. In the 
