50 
NEW OR CRITICAL BRITISH ALGAE. 
Phaeophila Engleii, RJce., Algenjl. der Westl. Ostsee.p. 86. 
Weymouth. On the shells of Spirobis nautiloides (on Fucus 
serratus). 
Thallus as in the preceding species, but with filaments much 
more sinuous and slender. (In my specimens the cells are from 
5-8 p in diameter and from 10-80 p long.) 
This interesting species appears to the naked eye as a green 
stain on the shells of the Spirobis. When viewed as an opaque 
object under the microscope the creeping green fronds and the long 
colourless hairs are clearly visible, but it is only after the shell has 
been dissolved by means of acid that the plant can be accurately 
studied. MM. Bornet and Flahault, in their paper on the per- 
forating algas (Bulletin de la Soc. Bot. de France, vol. xxxvi.), 
state that a species of Ochlochcete, which appears to be Crouan’s 
0. dendroides, v calcicola , Hansg., is frequently found mixed 
with Gomontia on various shells. We may expect this to occur on 
the coasts of Britain. 
Halicystis ovalis, Aresch ., Phyc. Scand. p. 221. 
Loch Goil. G. Murray, Kyles of Bute, G. Murray, and Prof. 
Schmitz. 
Mr. Geo. Murray and Professor F. Schmitz have been fortunate 
enough to discover, whilst dredging in the Clyde Sea- area, this 
most interesting alga, one of the most important that have been 
added to the British Marine Algal Flora for some years. This 
plant, originally described by Lyngbye under the name Gastvidium 
ovale (Hydrophyt., p. 72, t. 18 A), has been placed by all subse- 
quent writers, with the exception of Areschoug, in the genus 
Valonia , from which it differs in some not unimportant particulars, 
notably in the absence of pyrenoids. We are pleased to learn that 
Mr. Murray, in the forthcoming number of his “ Phycological 
Memoirs,” purposes to give an account of the structure and 
systematic position of Halicystis, for we trust that he will clear up 
many points, which at present are very doubtful, in this hitherto 
neglected genus. 
Ectocarpus brevis, Sauvageau, Journ. de Bot. ( Morot .), Vol. vi., p. 76, t. 
2, Jig. 11. 
Berwick-on-Tweed. On Ascophyllum nodosum. October, 1891. 
On examining some specimens of Asc. nodosum, gathered at 
Berwick in the autumn of last year, I found that they were 
covered with this very minute Ectocarpus , which has only lately 
been described by M. Sauvageau. When the fronds of the host- 
plant are wet the Ectocarpus is quite invisible, but when dry its 
presence is made known by its yellowish colour ; but the filaments 
are so short that ihey can hardly be detected by the naked eye. 
The endophytic portion of the frond is well developed, formed of 
irregularly-branched filaments, the cells of which are from 6 to 12 
p in diameter, variable in form, and much longer than broad in the 
more deeply immersed portions, where they reach a length of 24 
or 25 p, but short in the cortical portion of the host-plant. The 
