194 CLASSIFICATION OF THE YEASTS 



Genus II. Zygosaccharomyces. Barker 



Ascs preceded by a copulation, iso- or heterogamic, ascospores 

 with a thick membrane. 



Genus III. Debaromyces. Klocker 



Ascs derived from a copulation most often heterogamic, with 

 globular ascospores provided with a single verrucose membrane. 



Genus IV. Nadsonia. (Guilliermondia) Nadson 



Ascs derived by budding from a cell formed by heterogamic copu- 

 lation. Ascs with walls more or less thick. 



Genus V. Schwanniomyces. Klocker 



Traces of copulation ; ascospores with a single verrucose mem- 

 brane formed of two unequal parts girdled and provided with a pro- 

 jecting collar. 



Genus VI. Torulaspora. Lindner 1 



Round cells resembling Torula with a large fat globule in the center. 

 The ascs present only traces of copulation in their origin. 



THIRD GROUP 



Budding yeasts which form, in sugar solutions, at first a deposit, 

 and later on a more or less slimy scum without occluded air. Asco- 

 spores, round or oval, with from 1 to 2 membranes, germinating by 

 budding; generally produce alcohol. 



Genus VII. Saccharomy codes. Hansen 



Cells divide by a procedure intermediary between budding and 

 division. Frequently rudiments of a mycelium with transverse walls. 



Ascospores in a single membrane germinating in a single direction 

 in the form of a tube which swells up and separates the ascospore by 

 the formation of a transverse wall accompanied by a slight circular 

 constriction. Germination often preceded by parthenogamy. 



Genus VIII. Saccharomy copsis. Klocker 

 Ascospores in two membranes. 



1 This genus seems to be characterized by its traces of copulation as the 

 investigations of Rose have indicated. We have united these characteristics with 

 those provided by Linder to characterize this genus. 



