18 COCCOPHYCE. 
Apiocystis Brauniana. Mig. Einz. Alg. p. 69. 
Thallus pear-shaped, pallid green, the cavity filled up by 
gelatinous matter, in which are imbedded the gonidia, at first 
few, increasing in number with age, as far as 1600. 
Sizz. Frond -04--1 mm. high, gonidia ‘012 mm. diam., 
cells -0075--011 mm. (Rabh.). 
Rabh. Alg. iii. 43. Fresen. Beitr. p. 237, t. ii. f. 1-20. 
Henfrey in Micro. Journ., 1856, p. 52, t. 4, f. 26-27. 
Fresh water ditches, &c. 
Professor Henfrey found this plant in January, ina jar of water con- 
taining aquatic plants brought from Wimbledon Common six months 
previously. The development, as recorded by Nigeli, is detailed in the 
article quoted above. 
“The young ‘swarm cells’ (zoospores) attach themselves by their 
ciliated point (especially to Cladophora fracta), and become invested 
with a club-shaped, enveloping membrane. The first division of the 
green body then takes place in the direction of the axis of the vesicular 
envelope, and is repeated alternately in each direction of space. During 
this the vesicle in which the cells (gonidia) lie, continually expands, and 
generally becomes very evidently pedunculated. Young vesicles 
contain a regular number of cells, namely, 2, 4, 8, 16, 32, &c., but the 
number afterwards becomes indefinite; in largish vesicles, 1-50" 
(‘5 mm.) long and 1-120” (22 mm.) diam. I have counted about 300; 
in the largest, about 1-25” (-1 mm.) long and 1-50" (‘5 mm.) thick, some 
1,600 cells. 
“The cells (gonidia) are at first uniformly distributed over the whole 
cavity of the vesicle. Subsequently they generally become collected on 
the internal surface of the wall of the vesicle, where they lie in one or 
more strata, But the cell division always takes place in all directions 
of space, the cells situated internally advancing outwards towards the 
periphery. In old vesicles the cells are sometimes arranged in rings 
of eight upon the wall. When the family of cells is mature for 
‘swarming, which may occur at very different sizes and with very 
different numbers of gonidia, the cells begin to move, at first slowly, 
from their places, and then gradually to circulate more rapidly in and 
out about each other ; the vesicle bursts, and the gonidia emerge by the 
orifice which is formed. Sometimes the swarming is preceded by the 
state in which the cells are arranged in parietal rings. 
“The cells secrete an abundant gelatinous coating, which becomes 
softened within the vesicle, and confluent into a structureless jelly. The 
vesicle sometimes appears merely as the boundary line of the jelly; in 
general, however, it may be distinguished as a distinct wall composed of 
denser gelatinous substance, the internal outline of which is always 
distinct and sharp, while the outer is frequently indistinct, and partly 
dissolved.”— Nagelz. 
Plate VIL fig.1. a, young frond; } and, older fronds x 100 
diam.; d@, frond with cells undergoing segmentation X 200; e, part of 
frond with mature gonidia X 400; f, free gonidia; g, ciliated gonidia or 
zoospores X 400 diam. 
Inoderma lamellosum, Kutz., has been said to have occurred in 
Britain, but we have not been able to satisfy ourselves of its occur- 
rence. 
