70 VAN TIEGHEM AND LE MONNIER. 



terminal dichotomy contain sixteen spores, those of these 

 secondary lateral ones will only contain a single spherical 

 spore of from '005 to -006 mm. These spores, in germinating, 

 either rupture the closely-applied sporangium (fig. 20) or the 

 spore pierces its -svall, elongating directly into a hypha, and 

 leaving its basal portion enclosed. 



It is important to remark that in our cell-culture the fruc- 

 tification was often exclusively composed of dichotomous 

 hyphse with small sporangia, without a trace of the large 

 hyphse bearing a single sporangium. 



We have also observed the germination of the spores of 

 Thamnidium in a layer of a nutritive liquid, such as orange 

 juice, so arranged as to prevent, as far as posssible, the access 

 of air, and to prevent the plant from fruiting. Under these 

 conditions the spores absorb nutriment and swell into large 

 homogeneous spheres, which, by a process of gemmation, pro- 

 duce more or less irregular chains of sphaerous cells. When 

 the mycelium is subjected to the same treatment the hyphae 

 form also at their extremities chains of irregular joints, in 

 which the protoplasm temporarily condenses, and which are 

 an approach, therefore, to chlamydospores. Under the same 

 conditions we have also seen short branches of the hyphee 

 swell at intervals, often at their extremities, into large 

 spheres, with granular walls, and containing protoplasm 

 filled with large vacuoles. 



We have not as yet detected the zygospores of Tham- 

 nidium. 



Ch^etostylum. 



Fresenius in searching for Thamnidium discovered two 

 other Mucorini. One is Pijatocephalis Freseniana of De 

 Bary ; the other is the plant to which we have now given 

 the name of Chatostylum Fresenii} Fresenius believed it to 

 be a reproductive system belonging to Mucor Mucedo. It is 

 also very probable that it is identical with the reproductive 

 system ascribed by Klein to the same plant, and named by 

 hira Bulhothamnidium elegans? 



Chcetostylum occurs mixed with Chcetocladium upon horse- 

 dung, and closely resembles it in appearance. It differs, 

 however, in having a strictly definite instead of indefinite 

 mode of growth. It is heterosporangious, like Thamnidium^ 

 and may have large sporangia with a columella, and a difflu- 

 ent wall, terminating simple and vertical hyphse, or small 



1 Fresenius, ' Beitr. z. Mykol.,' 1863, p. 96. 



2 Kleiu, ' Verhandl. dev. k. k. Zool. Bot. Ges. in Wien,' 1870, t. xx. 



