FUJS T GI. 459 



brought to light another and a sexual means of reproduction, which is 

 described in tne cases of llhizopus nigricans, Ehrb., and Syzygites megalo- 

 carpus, Ehrb. These cases are, with the exception of unimportant details, 

 similar, and it will be sufficient to describe the process as it occurs in the 

 former. The conjugating cells of Ithizopus nigricans are elongated, stout, 

 irregularly brancning and interwoven tubes. Where two meet each 

 pusnes against the other a protuberance, at tirst cylindrical and of equal 

 thickness with itself. They remain closely attached and soon grow to a 

 considerable size, in thickness chiefly. At the end of each a separate cell 

 is formed by the growth of a partition. These two cells are usually of 

 unequal size one as long as it is broad, and the other only half as long 

 as its breadth. The original membrane which separated them now be- 

 comes perforated in the middle, and soon vanishes altogether; the two 

 conjugating cells then unite and form a zygospore, which increases rapidly 

 in size, and usually attains a diameter ol over one fifth millini. It is, as a 

 rule, drum-shaped ; the ends smooth, and the free surface clothed with 

 wart-like protuberances. The contents are of coarsely granular proto- 

 plasm, often accompanied by large drops of oil. The germination of the 

 /ygospore, as observed in Syzygites, is by means of a germ-tube, which by 

 repeated dichotonaous branching, at the expense of the stored-up matter 

 in the zygospore, soon forms a new mycelium bearing asexual sporangia. 

 .Professor Strasburger has very recently proposed the name of gametes 

 fur the conjugating cells, and zygote for the zygospore. Professor de 

 J3ary has further suggested that when the gametes are stationary, as in 

 this Order, they should be called aplanogametes, to distinguish them from 

 motile conjugating bodies found in Algce, which he would call plano- 

 yametes. The substitution of zygote for zygospore is on the ground that 

 the organ in question is not the equivalent of a spore, but of a fertilized 

 ovum. This nomenclature, if accepted (and it is time that some such 

 rational system were introduced), will necessitate the substitution of other 

 words for the terms oospore, &c., in other Orders. 



The Mucorini are usually to be found growing on horse-dung and de- 

 caying substances. 



HYPODEEMII. 



Diagnosis. Fungi parasitic on living plants, and consisting of 

 a mycelium of interwoven hyphse bearing asexual organs of repro- 

 duction (spores) either in definite or irregular receptacles. 



This Order is divided into two Suborders as follows : 



Suborder 1. UBEDI]OLE. Fungi parasitic on living plants, and 

 consisting of hyphse woven into dehnite fructiferous receptacula, at 

 tirst situated beneath the surface of the affected part, but at length 

 bursting out. The reproductive organs are of an asexual character, 

 no sexual organs being as yet known, and take three consecutive 

 forms, arranged so as to form a cycle of generations on two 

 different host-plants. 



