CEDOGONIACE^E. 153 



SECTION 1. Monoecious species. 

 A. Oogonia always destitute of median processes. 



a. Oospores globose or subglobose. 

 CEdogonium Fetri. Wittr. Mon. JEdog. p. 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. 



SIZE. Cells -OOG-'OO? 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 'Ol-'Oll 

 mm. 



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 Eabenhorst's measurements to 

 millemetres, and equally difficult to reconcile them. 



Plate LX VIII. fig. 1. CEdogonium Petri with oogonia X "400. 

 CEdogonium ciryptopoirum. Wittr. Dispos. (Ed. p. 19. 



Oogonia single, elliptic, or rather depressed globose, opening 

 by a median pore, almost rilling the oogonium, spermogoiiia 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-t)08 x 'OOT-'Oll mm. 



var. )3. vulgare. Wittr. 



Oogonia 2-5, continuous or single, spermogonia 1-4 celled, sub- 

 epigynous or hypogynous, or scattered. 



SIZE. Cells -005--OOS mm. 3-5 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 LXVI1I. fig. 2. CEdogonium cryptoporum. var. vulgare with 

 oogonia x '400 



