292 AQUATIC PHYCOMYCETES 



with a small bulbous swelling and a short rhizoid, both then increasing 

 somewhat in size, especially the more distal female structure, which 

 eventually receives the contents of the male, expands, and becomes 

 transformed into the resting spore, the latter germinating after a 

 short resting period (from two to three days) to form zoospores. 

 (Modified from Couch.) 



On Stigecclonium sp., United States; Oedogonium sp., Berczi (1940: 

 82, pi. 2, figs. 14-16), Hungary. 



Couch was unable to determine whether the gametes were borne 

 in sporangia with the zoospores or formed in separate gametangia 

 (see under "Sexual Reproduction," p. 71). The species is an exceedingly 

 interesting one, and further investigations on the nature and fate of 

 the motile bodies produced by the germinating resting spore and on 

 the cytological details of germination would be of greatest value. 



SECTION IV 1 



Rhizophydium transversum (Braun) Rabenhorst 

 Flora Europaea algarum, 3: 281. 1868 



Chytridium transversum Braun, Monatsber. Berlin Akad., 1855: 382; Ab- 

 handl. Berlin Akad., 1855: 44, pi. 4, figs. 1-6. 1856. 



Sporangium sessile, at first spherical, becoming broadly ellipsoidal 

 or fusiform, the apices strongly papillate, slightly curved at maturity, 

 up to 16.6 ix in diameter, with its long axis perpendicular to its point 

 of insertion on the algal cell; endobiotic part so far as observed con- 

 sisting of a slender unbranched rhizoid; zoospores ellipsoidal, with a 

 colorless basal globule, apparently emerging through pores formed 

 upon the deliquescence of the two opposite papillae (rarely, also, a 

 third, apical, papilla); resting spore sessile, subspherical or spherical, 

 outer wa'l smooth, yellowish, inner wall colorless, contents with from 

 one to two large globules, upon germination forming zoospores which 

 escape through an apical pore. 



On actively motile cells of Chlamydomonas pulvisculus, also pos- 



1 See also the following imperfectly known species of Rhizophydium: 

 R. asterosporum, p. 313 R. spirotaeniae, p. 315 



R. barkerianum, p. 314 



