132 NEMATOPHYCES. 
Monostroma Wittrockii. Born. Notes Alg. p. 176. 
Thallus membranaceous, gelatinous, bright green (18 mill.) 
oblong, pedicellate, at first saccate, then open at the summit, 
margin becoming irregularly lobed. The adult plant becomes 
sessile, and is attached by a part of its surface, when mature the 
fronds are large (8 cent. diam.), the lobes plicate, elongated 
and rounded, cell angular, subquaternate, in section of thallus 
rounded, chlorophyllose body occupying about half the cell. 
In salt or brackish water. 
Perhaps hardly claiming a place in this work, as it is more truly a 
marine species, 
Plate LI, fig. 8. Portion of a frond X 200. Fig. 9, 10, sections of 
frond x 200. Fig. 11, zoogonidia X 300. Fig. 12, germinating x 200, 
after Bornet. 
Monostroma bullosum. Wittr. Mon., p. 28, is the Tetraspora 
bullosa of this work, see p. 16, plate v1., fig. 1. 
Famity II. SPHAROPLEACEA. 
Threads simple, with terminal vegetation, very long, articu- 
late, articulations cylindrical, by spurious septa multilocular. 
Chlorophyllose mass distributed in annular bands, which enclose 
from 38-7 starch vesicles. 
Propagation by oospores after sexual fecundation, very 
numerous in the cells, at first green, then red, enclosed in a 
stellate sporoderm. 
Genus 57. SPHZEROPLEA. Ag. (1824.) 
Characters the same as given above for the family, which 
consists but of one genus, 
The following is an abstract of a memoir on Spheroplea annulina, by 
Cohn (in the “ Ann. des Sci. Nat.,” 1856, p. 187), describing the process 
of fructification :—“ The structure of the resting-spores is very singular. 
They are red spherical hodies, from one 120th to one 100th of a line in 
diameter, and formed of two hyaline membranes, the interior of which 
is intimately connected with its plastic contents, whilst the exterior is 
loose and elegantly plaited. These plaits or folds are so arranged that 
they meet at their two poles; often, however, they are very irregular 
in shape and direction, especially in the larger spores. 
“Tn germination the resting-spores undergo several modifications. They 
become granular and change to a dull brown red, and a more transparent 
circle appears in their centre. Frequently the red matter changes to 
green before the germination, and this change of colour is gradual, 
proceeding from the circumference to the centre of tho cavity. At 
length the whole of the plastic contents divides into two, then into four 
or eight bodies, which burst the double envelope and disperse in the 
water a8 80 Many zoospores, 
