180 NOTES AND MEMORANDA. 



not vary much in size (about 30 mmm.). Their granular con- 

 tents and large central oil-drops quite agree with those of the 

 smooth spores. The author thinks these are developed in a 

 different way from them. He sometimes noticed that the 

 haustorium of the male came in contact with the wall of the 

 female plant, and as a result of this contact a projection from 

 the body of the female, of an arched figure and already 

 covered with spines, is pushed out, the contents of both 

 gradually flowing thereinto, this projection becoming slowly 

 changed into the perfect resting-spore (a, o). The conjugating 

 Polyphagus-individuals, destined to produce spinous spores, 

 like the others, are found in groups ; they are usually larger 

 than the smooth-spored, as it were, better nourished. The 

 author leaves in doubt the question whether the smooth- and 

 spinous -spored Polyphagus-forms are to be regarded as two 

 distinct generations, constantly perpetuating themselves 

 (species, races), or as merely unessential variations of the 

 same species, as he did not succeed in rearing the two forms 

 pure through several generations ; possibly, he says, the 

 spinous form is the normal, and the smooth-walled form to 

 be regarded as resulting from a less vigorous vegetation. 



The author had not succeeded in observing the germina- 

 tion of the spinous spores, although he did that of the smooth. 

 In about a month their oil-drops diminished or were broken 

 into smaller drops; the protoplasmic mass then bored 

 through the wall, and came forth in the manner described 

 for the zoosporangia. Outside the resting-spore it became 

 changed to a zoosporangium, in which, around yellow nuclei, 

 the zoospores originated. Thus the sexually-developed 

 resting-spore of Polyphagus, to a certain extent, admits of 

 being regarded ^s a " resting-prosporangium." 



As to the systematic position of Polyphagus, it, without 

 doubt, belongs to the family Chytridiacese, especially as cha- 

 racterised by the mode of origin and structure of its zoo- 

 spores. During its period of vegetation it consists of a single 

 cell, and its numerous haustoria have an analogy in Chytri- 

 dium mastigotrichis. Since in Polyphagus the zoosporangium 

 becomes separated by a dividing wall from the vegetative 

 cell of the parasite (prosporangium), it might appear as if 

 this organism were bicellular, and belong to the genus Rhi- 

 zidium, to which, indeed, it was referred as R. Euglena by 

 A. Braun and Schenk. But the genus Rhizidium is, through- 

 out its life, bicellular, one cell of which is the ramified root- 

 cell, the other becoming the zoosporangium. This distinction 

 at once separates the two genera. They stand, however, in 

 close relationship, and form a special group, the Rhizidieae, 



