ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 73 



he describes the life-history of a number of forms, and then sets down 

 his own conclusions. He finds a natural series from the Chytridiales- 

 showing progressive evolution of the vegetative body and sexual process 

 up to the Oomycetes and Zygomycetes. He notes the double swarming 

 of the zoospores, reaching its highest development in Saprolegniace*, 

 and proliferation of the sporangia, both phenomena unknown in alga?. 

 These facts, he holds, point to the origin of the lower fungi from uni- 

 cellular organisms at the level of the Protomastignieae or Protococcoidea?, 

 either colourless or chlorophyll-bearing, rather than from confervoid or 

 siphonaceous alga?. Other reasons are adduced to support this view, as, 

 for instance, the form and ciliation of the zoospores in the Ancylistales- 

 and Oomycetes, which are totally different in the Chlorophyceae, as- 

 represented by (Edogonium and Vaucheria. There is also the difference 

 in fertilisation between these different forms, accomplished in the fungi 

 by means of an antheridial tube, in the alga? by ciliate or biciliate sperms. 

 Atkinson does not consider the number of cilia of the zoospores a very 

 distinctive character, as both kinds of zoospore may occur in the same 

 zoosporangium. 



The writer does not hold with the theory that parasitism has a 

 debasing influence, considering the group of fungi as a whole. There 

 is distinct progression of development from the Chytridiales to the 

 Oomycetes, all of them being parasitic. Again, the Ascomycetes and 

 Basidiomycetes show extensive development of the fruit-bodies undeterred 

 by the influences of saprophytism or parasitism. 



Development of Fungi on Fatty Substances.* — It has been generally- 

 held that fungi do not grow on fats. A. Roussy has made experiments 

 to test the validity of this statement. He found that fungi such as 

 Rhizopus nigricans, Phycomyces nitens, etc., grew best on a sugar solution 

 when there was only a small percentage of sugar. He applied the same 

 test to fats, using only small quantities along with Raulin gelatin, and 

 he obtained successful cultures. 



Leptolegnia from North Carolina.f — W. C.Coker has collected this 

 rare fungus from a jar containing alga?, and has cultivated it over a 

 year. It was first discovered and described by He Bary from mountain 

 lakes in Germany in 1881 and 1884, and Coker tells us it has not been 

 recorded since. The development of the fungus was followed, and 

 various details, omitted by He Bary, have been noted. 



Fungus Parasites of Alga?4 — The species described belong to the 

 Chytridiales, and are parasitic on filamentous green alga?. They were 

 collected by G. F. Atkinson in the vicinity of Ithaca. He recalls his 

 note on the escaping zoospores of Rhizophidium globosum, which come 

 to rest on the sporangial wall, and put out pseudopod-like extensions of 

 protoplasm that feel for the opening. The same phenomenon was- 

 observed in R. brevipes sp. n., parasitic on Spirogyra variant : if the 

 zoospore failed to find the opening with its pseudopodia, it came to rest 



* Comptes Rendus, cxlix. (1909) pp. 482-4. 



+ Mycologia,l. (1909) pp. 262-4 (1 pi.). 



X Bot. Gaz., xlviii. (1909) pp. 321-38 (8 figs.). 



