56 
NEW OR CRITICAL BRITISH ALG.E. 
External vegetative filaments unbranched, terminating in a hair, 
not attenuated, 12-14 /x in diameter, the cells as long, or a little 
longer than the diameter. Sporiferous threads scarcely raised 
above the surface of the gall and terminating in a globular or 
oval plurilocular sporangium, which is, however, sometimes shortly 
stalked and attached laterally to the basal cells of the external 
vegetative filaments. Sporangia 50-53 fx long, and 30-35 fx broad, 
rarely 72 /x long, very numerous, completely covering the surface 
of the gall. 
This minute species is about the size of Myriactis pulvinata , 
Kiitz., from which, however, the obtuse, not attenuated vegetative 
threads and plurilocular sporangia readily distinguish it. Hab. 
Biarritz, discovered by Dr. Bornet in June, 1870. 
Ectocarpus luteolus , Sauv. — This species forms alight yellowish 
down on the base of old stems of Fucus serratus and F. vesiculosus , 
of which the leafy part has fallen away, but of which the stems 
still live. The plant is not easily distinguished in the wet state, 
and should be looked for on a dry, sunny day. It does not occur 
on specimens of Fuci growing in the zone of Ascophyllum 
nodosum , but at a lower level in that of Himanthalia. The 
external portion of the plant forms an indefinitely extended 
cushion of branching threads, from which the erect filaments and 
those descending and penetrating the subjacent tissues originate. 
Erect filaments larger at the base than the summit, and terminating 
in a hair of one or several cells without chromatophores, very un- 
equal in size, 6-8 fx at the base of the free portion, length some- 
times 400 /X, usually from 100-300 /x, cells 1-3 times longer than 
broad, very indistinct. Plurilocular sporangia, terminating fila- 
ments arising from the base of the parasite or lateral on short 
branches of the longer threads, not very completely differentiated 
from the vegetative cells, 30-80 /x in length, 7-13 fx in diameter, 
often slightly torulose, chambers usually simple. 
Fclocarpus solitarius , Sauv., a species found on Dictyota dicho- 
toma , Dictyapteris polypodioides , and Taonia atomaria. — The endo- 
phytic portion small and irregular in shape, the external portion 
simple or slightly branched, bearing oval, plurilocular sporangia. 
[This species seems to be replaced on our shores by another closely 
allied species, which Mr. Holmes and I have recorded in our 
“ Revised List ” under the name E. parvulus , Kiitz. Dr. Bornet, 
however, considers that it is distinct from that species.] These 
eight parasitic species of Ectocarpus appear to form a natural 
group, for which, perhaps, Thuret’s name Streblonema might be 
adopted. 
The Muciferous Canals of the Laminariacece (Ann. Sc. Nat. 
Bot., xv., 1892, pp. 1-46, 20 figs.) 
M. L. Guignard, in a very interesting paper on the structure and 
development of the mucus canals of the Laminariacece , states that 
the tissues may be successfully fixed by a solution of chrome- alum 
and sea-water, and the mucilage then stained either with methyl- 
