MARINE PHYCOMYCETES 461 



found that numerous vacuoles, separated bv thin layers of cyto- 

 plasm, function in zoospore formation. Once formed, they are 

 active for a brief period and then encyst within the sporangium, 

 giving it a reticulate appearance. Encystment within the spo- 

 rangium seems, however, to be abnormal. ScherfTel (1925) be- 

 lieves that these methods of zoosporogenesis in Eurychasma are 

 not those of true chytrids but of Saprolegniaceae, and he would 

 therefore place it in this group. 



Reports of chytrids from the Pacific coast briefly describe 

 Chy iridium alar him [Kibbe (1916)] on Alarm fistnlosa and C. 

 codicola and Rhizophy diitm codicola on C odium miicronatum 

 [Zeller (1918)]. In a brief note Martin (1922) calls attention to 

 the fact that Polysiphonia sp. along the New Jersey coast is para- 

 sitized bv Chytridhim (Rhizophid'mm) polysiphoniae, and Spar- 

 row (1936) records the occurrence of this same chytrid on Poly- 

 siphonia fibrillosa and Ceraminm rubrum in the vicinity of Woods 

 Hole, Massachusetts. This pathogen is in turn parasitized by the 

 chytrid Pleolpidhnn (Rozella) marinum [Sparrow (1936)]. All 

 other known species of this genus occur in fresh water. 



Among the 15 species of chytrids collected by Sparrow (1936) 

 in the waters near Woods Hole, 2 are especially noteworthy. 

 One, Peter senia (Olpidiopsis) andreei, occurs on Ectocarpus sili- 

 cidosiiSj upon which it may be pathogenic. Its zoospores are later- 

 ally biciliate, as was first pointed out by Petersen (1905) and con- 

 firmed by Sparrow (1936). The other species, Thransto chytri- 

 dhim proltferum, occurring saprophytically upon Ceramium dia- 

 phamim and Bryopsis plumosa, is described as a new generic type. 

 Its sporangia are Thraustotheca-like in their discharge of zoo- 

 spores and sporangial proliferation. At the time of discharge the 

 zoospores lack cilia, but each may later come to have a single 

 anterior flagellum. 



In Karling's (1943) account mention is made of an organism 

 collected near Beaufort, North Carolina, which is parasitic on 

 Ectocarpus mitchellae and E. siliculosns and is Olpidium-like in 

 structure and development but possesses anteriorly uniflagellate 

 zoospores. Karling described it as Amsolpidium ectocarpii and 

 placed it in the family Anisolpidiaceae, which was to include 2 

 other genera and 5 other species, each having zoospores with a 

 single flagellum that rises anteriorly. Furthermore he believed 

 that the members of this family and those of the Rhizidiomyce- 



