148 ROLAND TIIAXTER ON TUE 



midway between the two conjugating cells in a fashion analogous to the similar process 

 in Spirorjyra. The intervening walls between these two gametes, or conjugating out- 

 growths, are then al)sorbed and a mingling of their contents ensues. A bud then aj)pears 

 (fig. 322) on one or both the gametes, which increases rapidly, as a rule apjjropriating 

 the entire contents of each conjugating cell to form the zygospore. A septation of the 

 hyphae above and below the point of conjugaticm is often seen, but is not invariable, 

 resembling in this respect the similar process in Conidioholus pre\'iously described. It 

 may be mentioned, in passing, that the chief distinction between the two rests on the 

 fact that here we have a zygospore fonned by Ijudding, while in Conidioholus the spore 

 is produced directly within one of the conjugating cells. In this, as in other cases, the 

 empty hj^phae disa]ipear rapidly after the zygospores have been formed; a circumstance 

 which, together with the I'apiditj^ of the process as a whole, accounts for the iiifrequency 

 with which conjugation in Emjnisae can be observed. In one case, however (^JS. rJiizo- 

 spora), the hyphae after conjugation become broAvn and horny, holding the spores firmly 

 in a spongy mass (fig. 371) ; but even here the process of conjugation can only be seen 

 during a short period, while the spore is developing, owing to the subsequent contraction 

 and distortion of the hyphae. 



In JE. echinospora, in which the zygospores are often external, a modification of this 

 Spirogi/ra-\\ke process is found, which deserves to be mentioned. Here (figs. 298-302) , 

 we have a conjugation taking place between two filaments in a manner similar to that 

 described above; but, instead of arising by budding from one of the gametes or in their 

 immediate vicinity, the spore commonly develops as a terminal swelling from the end of 

 one of the conjugating hyphae. 



In addition to these types of conjugation, a singular form, not, I believe, noticed hith- 

 erto in Entomophthoreae, occurs in _£/. Fvesenii. It is, as far as I have observed, invari- 

 able in this species and is never associated, as is usually the case, Avith the production of 

 azygospores. The hyphal bodies, as they occur in the host just prior to the production 

 of conidia or zygospores, are almost perfectly spherical and very uniform ; and are de- 

 rived from large, shapeless bodies which have the appearance of naked protoplasm. The 

 spherical hj'phal bodies lying side by side within the host proceed to conjugate in a man- 

 ner indicated in the succession of figures 127 to 135. A sHght projection first appears 

 from the upper inner end of either hyphal body (fig. 128). These projections soon 

 meet midway between the hyphal bodies (fig. 129), after which a bud begins to rise di- 

 rectly above their point of union (fig. 130). The contents of both bodies pass into this 

 bud, forming the mother cell of an elliptical z^^gospore which, I believe, aflbrds the only 

 known exception to the usual spherical shape. After the spore is mature, the two hyphal 

 bodies usually persist for some time as bladder-like appendages (figs. 135-136), which 

 sloAvly disappear (figs. 137-140). 



This is certainly a very simple process, yet it demonstrates I think, more clearl}' than 

 has yet been possible among Entomophthoreae the existence of an undoubtedly sexual 

 process of a distinctly zygosporic type. In Conidioholus, Basidioholus, and evi'U in the 

 examples from Emjmsa pi-eviously given, there is usually a more or less marked difler- 

 ence in the size of the gametes, which, in the first-named genus, led Brefeld to consider 

 the family as belonging to the Oosporeae; but, in the present instance, we have the ga- 



