RESEARCHES ON THE MUCORINI. 59 



the dye of M. Lange-Desmoulins. At length it made its 

 appearance on horse-dung placed under a glass shade in the 

 laboratory, and its long, isolated filaments developing at con- 

 siderable distances, one after another, proved that they origi- 

 nated by the germination of so mauy zygospores. This 

 enabled us to recommence a second series of cultivations, 

 especially as we received at the same time from the dye 

 manufactory a fresh fertile tuft of the plant. 



These facts ])rove that Phycomyces nitens may develope 

 in the most different media, oily or fatty, excrementitious, 

 horse-dung, or dyes. The only necessary condition is the 

 presence of fresh spores or zygospores. It is seldom met 

 with, only because the asexual spores speedily lose their 

 germinating power. Once established in a place favorable 

 for its complete development, it is indefinitely perpetuated by 

 zygospores, but it quickly disappears from localities where 

 the formation of zygospores is prevented. 



We have cultivated Phycomyces nitens (1) in pans on 

 cochineal dye, excrement, pounded cochineal, oranges, bread ; 

 (2j in cells on. horse-dung decoction, cochineal dye, orange 

 juice, and also our saline solution, both with and without 

 sugar. 



Spores. — The asexual spores of Phycomyces nitens, which 

 will serve as our point of departure, vary a little in form 

 according as they belong to the small sporangia of young 

 mycelium, or to the large sporangia which terminate the long 

 filaments arising from the adult mycelium. The first are 

 spherical (PI. Ill, fig. 2a), or slightly ovoid, 'OIG mm. ia 

 diameter; their centre is intensely yellow and granular j 

 their coat, on the contrary, and the peripheral portion of their 

 protoplasm colourless and homogeneous. The others are of 

 a very elongated ellipsoidal form, often flattened, or even 

 concave upon one of their sides, with a transverse diameter a 

 little less than that of the preceding ones, that is to say, '01^2 

 to '015 mm. ; they attain a length of "020 to •030 mm. (fig. 

 26); their central yellow matter forms an axile granular 

 band. It is, therefore, to the protoplasm of their spores that 

 the sporangia owe the golden-yellow colour which they possess 

 as long as their coat remains transparent and colourless. As 

 long as the spore is young its membrane has no distinct in- 

 ternal lining of protoplasm ; later on it separates, and acquires 

 a double contour ; at the same time the protoplasm becomes 

 more granular (fig. 2c). 



Placed in a moist medium, but in conditions which pre- 

 clude their development, the spores alter; the protoplasm 

 exhibits granules which become larger and larger, and finally 



