2 2 American Quarterly Microscopical Journal. 



SAPROLEGNIA. 



I can give no specific designation to the plant which I have 

 included under this genus, for, as far as studied, there were 

 presented characters different from descriptions to which I 

 have had access ; and yet I can not justly place it under a dis- 

 tinct species, since I have not been able to study the several 

 modes of reproduction, in which rest very important characters. 

 It is a form which seriously attacked Menobranchus kept at dif- 

 ferent times in a tank at the University. They seemed to pro- 

 duce considerable irritation, and death was sure to take place 

 in a few days. In the cases noted, the plants first appeared just 

 anterior to the brain, then posterior to each set of gills, and, 

 finally establishing itself on portions of the body and legs 

 soon completely covered the whole animal. 



This is quite different from the way in which I have since 

 noticed other forms to attack fishes, for with them growth took 

 place equally on a large portion of the animal, the filaments 

 being of the same age and covering the whole body. I have 

 already noticed the effect of this plant upon the animal, i. e., 

 that long before death, the parts infested had the appear- 

 ance of decomposing flesh, and could be easily torn from 

 the animal before the filaments would break ; the parts thus 

 exposed had the appearance of being inflamed. 



The fungus appears in dense, grayish mats of filaments, 

 averaging about 6 mm. in length, and when closely 

 observed the Sporangia are just noticable from their darker 

 appearance. (PI. VI., Fig. i.) Carefully removing a cluster 

 of filaments by means of a pair of forceps, and placing it under 

 a cover-glass, a great difference is noted in different filaments 

 according to age. When young the tip is always clear, while 

 just below it becomes very dark from its granular contents, 

 these granules becoming less dense so that the main part of 

 the filament is nearly clear. 



As they reach their growth the granules concentrate more at 

 the apex, and, after becoming so dense as to render that por- 

 tion of the filament opaque, a septum is formed producing 

 a terminal cell with a length some eight times its breadth. 



This sporangium is always larger than the filament; is 

 sometimes cylindrical, but generally club-shaped. In four 

 hours after the septum is formed, "the granules have so re- 

 arranged themselves as to produce a mottled appearance shown 



