SPOROBOLOMYCES 



191 



When a yeast cell is forming a spore on a sterigma, the young 

 spore, like a young bud, is devoid of a nucleus (Fig. 96, a-d) ; but, 



Fig. 95. — Sporobolomyces roseus. To show nuclei and the division of nuclei in 

 the yeast cells. Cultures made on malt-agar. Cells fixed with formalin- 

 acetic-alcohol and stained with iron-alum haematoxylin. A, a colony 

 of yeast cells y y which have been produced from two spores s s. With 

 the exception of a young bud attached to the uppermost spore, all the 

 yeast cells, as well as the two spores, each contain a single nucleus. 

 B, isolated yeast cells from various colonies. Each cell contains a single 

 nucleus and some of the cells are vacuolated. C, the division of the 

 nucleus in a budding yeast cell : a, the bud is as yet without a nucleus ; 

 b, the nucleus of the mother-cell has passed to the neck between itself and 

 its bud and is there dividing ; c, the nucleus has just divided into two 

 daughter nuclei ; d, the daughter nuclei have separated and now show 

 their nuclear membranes and nucleoli ; e, the bud is about to separate 

 from its parent cell ; its nucleus has grown in size. Drawn by A. H. R. 

 Buller and Ruth Macrae. Magnification, 2234. 



when the spore has attained almost full size, the nucleus of the parent 

 cell passes into the base of the sterigma and there divides (c-h). Of 

 the two daughter nuclei one passes through the neck of the sterigma 



