THE PATHOGENIC FUNGI 



979 



sporangiospores develop which are freed by its rupture. Sexual 

 reproduction, which is less frequent, consists in the fusion of the tips 

 or lateral processes of two neighboring hyphae, which form a large 

 spore covered with a warty membrane, known as a Zygospore. No 

 exospores are formed by the mucors but chlamydospores are numerous. 



FIG. 107. MUCOR MUCEDO. 1. Sporagium, c. columella, m. sporangium capsule 

 sp. spores. 2. Columella, after bursting of sporangium. 3. Poorly developed 

 sporangia. 4. Germinating spore. 5. Emptying of sporangium. 

 Brefeld.) 



(After 



The common laboratory contaminants are Mucor mucedo a constant in- 

 habitant of horse dung, and Mucor pusillus, which can usually be obtained 

 by allowing a piece of moistened bread to stand in a covered Petri dish. 



Mucor corymbifer (Lichteimia corymbifera) differs from the preceding 

 species in having pear-shaped instead of spherical sporangia born in loose 

 clusters on hyphae which are not raised above the surface of the medium. 

 This species is pathogenic for rabbits, and has been reported as the cause 

 of inflammations of the auditory canal and of other infections in man. 



ASCOMYCETES 



In this group are included all fungi which form ascospores. The 

 majority have a mycelium made up of septate filaments and repro- 

 duce by means of conidia which are frequently born on characteristic 



