138 



ROLAND THAXTER ON THE 



broken up, through the formation of partition walls, into numerous irregularly lobulated 

 fragments which correspond to hyphal bodies, as I use the term. These lobules appear 

 early in the development of the hyphae, in the form of irregularly swollen projections 

 from them; and mark the points of origin, even at an early stage, whence the conidio- 

 phores are subsequently to arise. Shortly after this general disintegration of the hy- 

 phae, single, simple conidiophores arise from each fragment, in number corresponding to 

 the swellings above described, and produce large, ovoid conidia which are discharged in 

 the usual way. The chief interest of the genus lies, however, in the formation of its rest- 

 ing spores, which seem to be of sexual origin. This formation of zygospores appears 

 as that of the conidia begins to disappear, so that both forms are at first developed side 

 by side, while eventually the conidial formation ceases entirely, — a circumstance which 

 seems to verify this author's previously expressed opinion that an alternation of some 

 regularity exists between the appearance of the two types of reproduction. In the for- 

 mation of these zygospores, hyphae arise from swollen projections, similar to those 

 already described as being the origin of the conidiophores, which, after a variable devel- 

 ment, conjugate through the apposition of their swollen extremities, the contents of one 

 extremity uniting with that of its fellow through the absorption of the intervening 

 walls, and producing in one of them a thick-walled zygospore. Owing to a difference 

 in size of these conjugating extremities, Brefeld was inclined to place the family among 

 the Oomycetes; but the previous observations of Nowakowski 1 in Empusa, together 

 with more recent studies of the family, render this improbable. In from ten da} r s to five 

 weeks after their formation, the resting- spores were made to germinate; and sending out 

 one or more hyphae produced usually a single conidium resembling those characteristic 

 of the species. Of these, two are described: Conidiobolus utriculosus and C. minor, 

 neither of which has been observed in the United States. 



The genus Basidiobolus, discovered by Eidam, is perhaps the most interesting of the 

 Entomophthoreae from the unusual differentiations which accompany its asexual as well 

 as sexual reproduction. Unlike other members of the group the species are wholly sa- 

 prophytic, occurring naturally upon the dung of frogs and lizards after evacuation; while 

 they maybe readily cultivated in nutrient solutions similar to those employed by Brefeld 

 in his study of Conidiobolus. According to Eidam, the fungus is present in the digest- 

 ive tract, only in the form of spores or hyphal bodies which are dormant until they are 

 evacuated with the faeces upon which they subsequently develop, forming large color- 

 less hyphae with numerous cross partitions. These hyphae do not become broken up 

 into hyphal bodies before reproduction commences, except in so far as this condition 

 may be approached in cases similar to that figured by Eidam 2 where, in a concentrated 

 nutrient solution, the segments of the hyphae become rounded; but do not, however, 

 break apart as in Conidiobolus. In reproduction the hyphal segments may produce 

 slender single conidiophores which, rising vertically, become greatly swollen at their ex- 

 tremities. From the apex of this conidiophore the large conidium buds and, during its 

 formation, the swollen extremity which bears it becomes modified by the contraction and 

 thickening of its walls into a peculiar piece or basidium, which is discharged, together 

 with the conidium, by the explosion of the slender conidiophore. 



H. c, a. 



2 1. c, PI. ix, fig. 10. 



