274 CLASSIFICATION OF SACCHAROMYCETACE^. 



Further particulars on this synonym are given at the beginning 

 of the description of the individual species. 



The second principal group of the true Saccharomycelacece is 

 composed of the genera Pichia and Willia, and is characterised by 

 the production of a film on the surface of the nutrient solution 

 immediately after the same has been inoculated. Hansen had 

 already discovered a representative of each of these new genera, 

 and at that time called them Sacch. membrancefaciens and Saccli. 

 anomalus respectively. Similar species were afterwards discovered 

 and described by other workers, Pichi, for instance, identifying 

 some which may be ranked with Sacch. membrancvfaciens, whilst 

 Will and his pupils found others of the type of Sacch. anomalus. 

 Consequently, Hansen named his new genera Pichia and Willia^ 

 in honour of these workers. 



In conclusion we give the following 



Analytical Summary of the Genera of the Saccharomycetacece 

 Family, 



The Saccharomycetacece exhibit the following general charac- 

 teristics : Monocellular, sporogenic budding fungi. Typical 

 mycelium is formed only by a few species, but all produce yeast 

 cells abundantly. Each cell is a potential sporogenic cell. The 

 spores are monocellular. The number of spores in each parent 

 cell (Ascus) is usually 1-4, seldom as high as 12. 



(1) Spores oval, round, pileate or lemon-shaped, with or without project- 

 ing rim, see 2. 



Spores acicular or spindle-shaped, sec 7. 



The cells form sedimental yeast immediately in saccharine nutrient 

 liquids, films being produced only later (if at a'l), see 3. 



(2) The cells produce a film at once on the surface of saccharine nutrient 

 liquids ; the film appears dry, owing to included air bubbles, see 6. 



(3) Spore with single membrane, see 4. 



Spore with two membranes. .... Saccharomycopsis. 

 The cells fuse together. ..... Zygosaccliaromyces. 



(4) No fusion of the cells occurs, see 5. 



The spores germinate by ordinary gemmation . Saccharomyces. 



(5) A promycelium is developed in the germina- 

 tion of the spores, and from this budding proceeds 



with incomplete separation Sacc/taromycodes. 



(6) Spores round or hemispherical, or irregular 



and angular. No fermentation Pichia. 



Spores pileate or lemon-shaped with projecting rim Willia. 



(7) Spores acicular. Parasitic on water-fleas . Monoxpora. 

 Spores spindle-shaped, almost filamentous, with a 



long flagellum ; parasitic on hazel-nuts . . . Nematospora. 



278. The Genus Saccharomyces, with the Genera 

 Hansenia and Torulaspora. 



The cells of the species belonging to the genus Saccharomyces 

 (E. C. Hansen) produce simple membrane spores which gemmate 



