34 AQUATIC PHYCOMYCETES 



mineral-salt solution; (2) 2.5 gm. dextrose, 0.5 gm. ammonium nitrate, 

 500 cc. mineral-salt solution, and 3 gm. agar; (3) 0.5 gm. ammonium 

 nitrate, 50 cc. cellulose suspension containing about 0.5 gm. of cellu- 

 lose, 3 gm. agar, and 450 cc. mineral-salt solution. The cellulose used 

 in (3) was precipitated with sulfuric acid. The mineral-salt solution 

 consisted of the following: 0.3 gm. K 2 HP0 4 , 0.2 gm. KH 2 P0 4 , 0.2 gm. 

 MgS0 4 .7H 2 0, 0.1 gm. NaCl, 0.1 gm. CaCl 2 .3H 2 0, 0.01 gm. FeCl 2 . 

 4H 2 0, 0.001 gm. ZnS0 4 .7H 2 0, and 1000 cc. of distilled water. The 

 pH of the mineral-salt solution was adjusted to 7.2 by the addition 

 of N/20 NaOH. She found certain differences among the fungi she 

 studied with respect to their capacity to live on these media. 



Two-membered cultures, that is the host and its endophytic parasite, 

 have been reported by Emerson (1950) for the chytrids Rozella achlyae 

 and R. allomycis. 



Whether or not certain so-called "chitinophilic" and "keratinophilic" 

 chytrids are confined to chitin and keratin, respectively, in nature seems 

 unlikely in view of the findings of Antikajian(1949) and Ajello( 1948b). 

 Antikajian dealt with Aster ophlyctis sarcoptoides, an inhabitant of in- 

 sect exuviae, and Ajello (1948b) recovered Polychytrium aggregatum 

 from soil by means of chitinous bait. Both these fungi grew well on a 

 medium composed of 1.0 per cent dextrose, 0.1 percent Difco yeast 

 extract, 0.1 percent Bacto-peptone, and 2.0 per cent agar. 



Among the members of the Blastocladiales considerable work on 

 isolation and culture has been accomplished. Butler and Humphries 

 (1932) secured outgrowths of Catenaria anguillulae, a filamentous form, 

 from infected liver-fluke eggs and obtained growth from zoospores, 

 when the latter were placed in fluke-ova extract and flaked egg albumen. 

 Growth of zoospores also occurred in this medium when agar (0.25 

 per cent) was added to it. Couch (1945a) also cultivated this fungus 

 in pure culture. He used liver extract-liver paste agar without sugars. 

 Allomyces, which is a filamentous form with indeterminate hyphal 

 growth, presents no special problems. It has long been isolated and 

 under cultivation. With such coenocytic forms as Blastocladia and 

 Blastocladiella, however, both of which have a determinate or restricted 

 growth, special difficulties arise because of the lack of hyphae in any 

 significant amount. Handling of Blastocladia is further complicated 



