NEW OR CRITICAL BRITISH ALG JE. 
51 
external filaments are very short, rigid, simple, obtuse, never pro- 
longed into a hair, and sometimes slightly attenuated towards the 
base, where they immerge from between the cells of the host. 
Cells 8-10 p in diameter, equal to or a little longer than broad. 
The external filaments composed of from 5-8 cells only. Plurilo- 
cular sporangia, oval or oval-lanceolate, 30-50 p long, 15-20 p 
broad, terminal, or more rarely becoming lateral owing to the con- 
tinued growth of the filament below the sporangium. The plant 
forms yellowish brown patches, indeterminate in form on old 
fronds of Ascophylla. 
Ectocarpus parasiticus, Sauvageau, l.c. p. 92, t. HI., jig. 20-23. 
Weymouth. In the fronds of Ceramium rubrum and Ggstocto - 
nium purpurascens. September, 1892. 
Filaments in the early stage growing in the axis of the host- 
plant, ultimately forming more or less limited dark spots in the 
cortical layer, composed of many creeping and a few erect threads. 
Cells of the endophytic threads longer and narrower than those 
near the surface, varying from 8-30 p long and from 2-10 p broad. 
Chromatopbores one in each cell, forming a parietal disc. Spori- 
ferous threads unbranched, crowded in minute darker spots on the 
brown patch, forming clusters about 1 m.m. in diameter, composed 
of densely packed threads by which the cortical layer of the host- 
plant is sometimes ruptured. Some of the external threads are 
true hairs, long and colourless, growing by cell division at the 
base. Others, 6-8 p in diameter and 60-90 p long, are formed of 
cells 6-12 p long, with larger chromatophores than the endophytic 
threads. Assimilation threads mostly terminated by a rounded 
cell, or sometimes prolonged into a hair. Plurilocular sporangia 
sessile, or on a pedicel composed of one or two cells, about 50 p 
long and 9 or 10 p broad. Divisions of the sporangia sometimes 
simple, sometimes divided into two longitudinally. Unilocular 
sporangia not observed. 
Microcoryne ocellata, Strom/., Notarisia , 1888, t. 3. 
Weymouth. On Castagnea Griffithsiana. September. 
Fronds very minute, from 2-5 mm. high, simple and clavate or 
shortly forked, composed of a central axis of colourless filaments 
rather loosely united with a solid mass ; peripheral layer of short 
horizontal filaments packed in a gelatinous substance. Cells of 
the peripheral filaments 10-20 p long and 5-8 p broad, each con- 
taining four or five round chromatophores. Plurilocular sporangia 
formed by transformation of the peripheral filaments, cylindrical or 
spindle-shaped, 50-70 p long and from 5-10 p broad, crowded at 
the base of the unchanged filaments of the peripheral layer. Divi- 
sions of the sporangia simple at the base and apex of the sporan- 
gium, but longitudinally divided into two in the middle. 
This very curious and interesting alga, which might be mis- 
taken for very young plants of Castagnece or Mesoglece , had, pre- 
vious to its discovery at Weymouth, only been recorded from the 
single locality on the coast of Norway, where it was discovered by 
