Observations on Saprolegniea. 21 



placed in the closet only a portion of its head and feet were 

 covered, while at the time of being removed, a dense mat of 

 radiating, branched filaments enveloped the whole animal. All 

 the forms which I have met have either developed from decay- 

 ing animal or vegetable matter, or caused its decay by their 

 growth ; and filaments separated entirely from all matrix, and 

 placed under cover-glass, the whole covered by a bell-jar to 

 keep it moist, showed, after some growth, that the protoplasm 

 did not half fill the filaments. Hence, after this brief view, I 

 have come to the conclusion that, according to the distinctions 

 of the two groups given by our authorities, this family of truly 

 parasitic plants must belong to the Physomycetes among the 

 Fungi, where it is placed by Sachs (7,242) and Cornu. (2, 5). 



M. Cornu (2) separates the entire family into two main divi- 

 sions — the Saprolegnieae proper, and the Monoblepharidae — the 

 chief distinction lying in the zoospores, which, in the first group 

 are uniform with two unequal cilia, one attached at either end, 

 or oval with two equal cilia attached in front ; while in the 

 second group they are ovate, and provided with a simple cilium. 

 Moreover, it has been noted that in all the species of the Sap- 

 rolegnieae proper the wall of the filaments is formed of cellu- 

 lose, giving a bluish reaction on the application of Shultze's 

 solution, whereas in the Monoblepharidae no reaction is given, 

 showing that the walls are not formed of cellulose. Under the 

 first division are included six genera, among which I have paid 

 special attention to but two ; Saprolegna and Ac/ilya, and of 

 which I shall treat further on. The second division contains 

 but a single genus. Monoblcpharis^ and under that but three 

 species have been described, while one of the forms which I 

 shall consider further on doubtless adds a fourth. 



To the Saprolegnieae are attributed two modes of reproduc- 

 tion, which give the group particular interest. In one case, 

 zoospores are produced which germinate and grow without the 

 intervention of any male product ; while in the other both male 

 and female organs are present, and fertilization takes place 

 giving rise to a spore, which remains at rest a much longer 

 time before germinating than in the former case. The first of 

 these methods I have carefully studied, and a full description 

 follows under the genus Saprolegnia j while the second form has 

 been particularly noted in the genus Achlya. 



