CDOGONIACES. 153 
Szcrion 1. Moncecious species. 
A. Oogonia always destitute of median processes. 
a. Oospores globose or subglobose. 
Gdogonium Petri. Witir. Mon, Hdog. De 6. 
Oogonia single, very rarely binate, pear-shaped globose, open- 
ing by a pore a little above the middle. Oospores rather 
depressed globose, almost filling the oogonium; spermogonia 
1-2 celled, hypogynous or epigynous ; spermatozoids single (?), 
terminal cell obtuse. 
Siz. Cells :006--007 mm., 5-7 times as long; oogonia 
021-024 mm, x °022-:029 mm.; oospore ‘020-23 x 
017-019 mm.; cells of spermogonia :0055-:006 x 01-011 
mn. 
Kirch. Alg. Schles, p. 51, 
Ireland. 
Having carefully measured a great number of the species here re- 
corded, and found Wittrock’s measurements universally accurate, we 
have given his dimensions throughout for all the species recorded by him. 
Unfortunately it is not easy to reduce Rabenhorst’s measurements to 
millemetres, and equally difficult to reconcile them. 
Plate LXVIII. fig. 1. Cidogoniwm Petri with oogonia X '400. 
Gdogonium cryptoporum. Witir. Dispos. Gd. p. 19. 
Oogonia single, elliptic, or rather depressed globose, opening 
by a median pore, almost filling the oogonium, spermogonia 2-7 
celled, scattered. Spermatozoids single (?). 
Size. Cells 007-009 mm. 4-6 times as long; oogonia 
*024--025 x :026--027 mm.; oospore *022-023 X :019--021 
mm.; cells of spermogonium ‘006-008 x ‘007-011 mm, 
var. B. vulgare. Wittr. 
Oogonia 2-5, continuous or single, spermogonia 1-4 celled, sub- 
epigynous or hypogynous, or scattered. 
Sizz. Cells -005-:008 mm. 38-5 times as long; oogonia 
*018--025 x 018-026 mm.; oospore ‘016-:022 x ‘013-018 
mm.; cells of spermogonium ‘005-'007 x *009--012 mm. 
Kirch. Alg. Schles. p. 52. Wittr. Mon. p. 7. 
Britain. 
We have only seen the variety, from the West of England. The type 
form has not yet been found in Britain. 
Plate LXVIII. fig. 2. Cidogonium cryptoporwm. var, vulgare with 
oogonia x °400 
