294 Bibliographical Notices. 



II. PemcUlhim-form.- — Under defective nourishment, the spores 

 of Mucor, instead of producing the m j'celium of Mucor, produce that 

 of PenicUlmm. The author has observed this fact five times in 

 Ehizopus and several times in M. vuhjaris. The same result follows 

 if the spores are too old, as was observed in M. canhms, M. roma- 

 nus, and M. vulr/at-is. Moreover a normal mucorean mycelium may 

 be transformed into a mucedinous mycelium, in which ease the 

 septa (which are few in Mucor) multiply until the filaments are 

 qiiite septate, as in true mucedinous filaments ; at the same time 

 the protoplasm becomes oily, and exhibits very regular and nume- 

 rous cavities. The formation of septa and the change in the proto- 

 plasm are the certain signs of the change of a mucorean into a mu- 

 cedinous filament;, whatever may be the nature of the mucedinous 

 fructification which it may ultimately bear. In a species of Mucor 

 the author has observed the fructification of PenkiUium proceeding 

 from the base of the cell which supports the sporangiiim ; but the 

 Mvcor-vaycclmm maj' become metamorphosed in the same waj^ be- 

 fore normal fructification, and yield only mucedinous fruit. When 

 3/Moor-spores are sown on the pulp of an orange, the mycelium 

 sometimes penetrates the pulp and appears on the sides transformed 

 into PeniciUium. It is not an exception or an anomaly, but a general 

 rule, that the Mucor inea; can pass into the form of PeniciUium. The 

 cause of this transformation is defect of nourishment. The Mucors 

 require considerable quantities of nitrogenous matters, whilst cer- 

 tain Mucedinecp, especially PeniciUium, can live on an exhausted 

 soil. It is doubtful whether PeniciUium can reproduce 3Iucor di- 

 rectly, although perhaps such reproduction may take place through 

 the macroconidia. 



III. Botrytis-form.—l^ Mucor romanus is cultivated on cats' 

 dung, it forms a strong myceliiim : but after the second day the 

 mycelium becomes septate, and on the third day it becomes alto- 

 gether mucedinous. The transfomied filaments grow and form a 

 dense fleshy mass, which may be cut with a knife like the flesh of 

 the large fungi. The mass is ultimately of a deep golden-yellow 

 colour. Under the microscope, it is seen to consist of interlaced 

 filaments crowned with a bunch of spores. This new mucedinous 

 fungus is like one found by the author in Belgium and at Home 

 upon excrement, especially of cats. Without regard to physiology, 

 the two forms might be united. The yellow coloiir of the mass is 

 attributable to the spores, which, although evidently mucedinous, 

 have entirely the nature of the spores or macroconidia of Mucor 

 romanus. These spores, if sown on an orange, germinate imme- 

 diately and produce a vigorous JiHcor-mycelium. The mj'celium at 

 the end of the second day produced the sporangiferous cells of Mucor 

 romanus. The allied form above alluded to behaves in the same 

 way, but does not produce Mucbr romanus ; it gives rise to quite a 

 difi:erent Mucor, very near Mucor romanus. The author knows 

 two other analogous forms of Mucedinecv which produce in germina- 

 tion a mucorean mycelium without any intermediate mucedinous 

 form. 



