]02 



MEDICAL MYCOLOGY 



ab jointed and transi'ormed into spores, corresponding in size and form to 

 those of Mncor but borne on the outer, rather than on the inner, surface of 

 sporangia. 



The series may be continued in Blakeslea trispora (Fig, 6). Under certain 

 environmental conditions, e. g., saturated atmosphere, this species forms 

 typical multispored sporangia with large pyriform columellas (Fig. 6, 1). 

 These sporangia show a marked tendency toward degeneration: with a slight 

 alteration of cultural conditions, they decrease in size and spore number, and 



Fig. 6. — Blakeslea trispora. Modifications of sporangia: 1, original form; Z, reduced form 

 without columella ; 3-5, formation of exogenous sporangioles ; 6, sporangiospore from sporan- 

 giole. {1-5 X260; 6 X720.) (After Thaxter 1914.) 



the columella shrinks or disappears. The resulting forms only distantly re- 

 semble the original sporangium (Fig. 6, 2). Where conditions of growth are 

 normal, the spore protoplasm migrates into protrusions, borne on spherical 

 sterigmata (Fig. 6, 3). Meridianal fission divides each of these into 3 spores 

 adorned with little apical tufts of hair (Fig. 6, 5) . The mature protuberance 

 separates from its sterigma or with its sterigma from the sporangium and is 

 disseminated (Fig. 6, 4). Here spore formation is further retarded; between 



