674: MISS RATHBONE ON MYRIACTIS ARESCHOUGII 
Myriactis -stellulata are figured by Harvey in his ‘ Phycologia 
Britannica,’ though, as Mr. Batters pointed out, they are there 
wrongly described as paranemata. 
Cor.opEsME cantrornica, Ajellm. (Adenocystis californica, 
Rupr.). (Pl. 24. figs. 5 & 6.) 
This alga, which grows upon Cystoseira and Halidrys, resembles 
Myriactis Areschougii in sending penetrating rhizoids into its 
host. 
In the young stages of the parasite the rhizoids are but few, 
and, apparently, Co¢lodesme does not send out the long wandering 
filaments of M. Areschougii, but, in the mature plant, from the 
base of the thallus a dense mass of fine rhizoids can be traced in 
the cell-layers immediately beneath the base of the parasite. 
These rhizoids run in the substance of the cell-walls, and com- 
pletely surround the cells of the host. When seen in longi- 
tudinal section under a low power, this habit gives the infected 
portion of the host-thallus a curiously opaque and ribbed 
appearance. The penetrating filaments of this alga appear to 
have been overlooked by other writers. Ruprecht, the author 
of the species, states that Cotlodesme californica never has root- 
fibres (Wurzelgeflecht); and Kjellman, who fully describes and 
figures the vegetative and reproductive portion of the thallus, 
merely alludes to an almost hemispherical adherent disc 
(hiftdyna). 
In conclusion, I wish to offer most hearty thanks to the staff 
of the Botanical Department of the Natural History Museum, 
not only for permission to work there, but also for much 
kindness and assistance. My thanks are also due to Miss Ethel 
Sargant for lending me slides and giving me material of Myriactis 
stellulata, and to Mr. Batters for information on the differences 
between the genera Flachistea and Myriactis; to Mrs. Antony 
Gepp also, under whose direction this work has been carried 
out, I am indebted for a large amount of kind help and advice. 
LITERATURE. 
Myriactis Areschougii. 
Batters, E. A. L.—Marine Alge of Berwick-on-Tweed. 
Reprinted from Berwickshire Naturalists’ Club Trans. 1889 
(Alnwick), p. 71. 
—— Additional Notes on the Marine Algwe of the Clyde Sea 
Area, Journ. Bot. vol. xxx., June 1892, p. 173. 
