2 1 8 VA UCHERIA. PAKT n. 



filaments by repeated bisection. According- to the ob- 

 servations of M. Itzigsohn, the endochrome in certain 

 filaments of Spirogyra breaks up before conjugation 

 into little spherical aggregations, which are gradually 

 converted into nearly colourless spiral filaments, having 

 an active spontaneous motion, and therefore corre- 

 sponding precisely to antherozoids. With the exception 

 of South America, the Conjugatse are widely dispersed 

 in warm and temperate climates. 



The genus Vaucheria may be assumed as a type 

 of the Siphonese, whose essential character is, that the 

 plant consists of one single tubular cell, however 

 branched and complicated its form may be. The Vau- 

 cherias form tufted masses of branching tubes, filled with 

 bright green granular matter, on mud and damp soil; they 

 abound in fresh-water pools, and some grow in the sea. 

 When about to produce fruit, the extremities of some 

 of the tubes swell out in the shape of a club, in which 

 a portion of the green matter collects, takes a darker 

 hue, and is separated from the rest by a transparent 

 space and a new envelope. After various changes, the 

 darker green matter forms itself into a zoospore, which 

 is so active that it breaks open the top of its club- 

 shaped cell, and comes into the water ; sometimes 

 several come, one after another. They are egg-shaped, 

 with a colourless beak, and as their whole body is 

 bristled with cilia, they leave a long current in their 

 wake when they swim, which they do with such impetus 

 that they are flattened against any obstacle they meet 

 with, even to the discharge of their green endochrome. 

 They escape from their cell about eight in the morning, 

 move for two hours, then come to rest, and begin to 

 grow into a new plant. 



M. Prihgsheim discovered another mode of repro- 

 duction in the Yaucherias, which are monoecious plants, 

 that is to say, the same plant produces snake-like 



