3 J: 8 FRESH-WATER ALG^. \C1iloro8perme(B. 



is called into life by the returning heat and moisture of 

 earl}' spring. 



What is recorded by M. Unger respecting Vaucheria 

 clavata, is exceedingly interesting. He set himself uninter- 

 ruptedly to observe one of the tubercles of fructification, 

 and when he had done so for half an hour, it became darker 

 in its colour, and a little transparent at its extremity ; in 

 the middle it was somewhat contracted, and had some traces 

 of spontaneous motion. He could scarcely believe his eyes 

 when he perceived the contraction to become more decided, 

 and a cavity to be formed at the base. The contraction at 

 length divided the globule into two smaller globules, wliich 

 moved spontaneously towards the summit. As the develop- 

 ment proceeded, the cavity and the uppermost globule 

 became enlarged, while the inferior globule became dimi- 

 nished ; the latter at length disappeared, and the remaining 

 large globule escaped by a terminal orifice ascending till it 

 reached the surface of the water. The whole process occu- 

 pied about a minute. On various other occasions he ob- 

 served numbers of these globules swimming freely about 

 here and there, stopping, and again setting themselves in 

 motion, exactly like animated beings ; and he does not 

 scruple to call them infusory animalcules. AVe have no 



