MlCROSPORA 177 



Filaments cylindrical ; cells not at all inflated, about 8/z (7.5- 

 9.5//) in diameter, 1-3 times as long; chromatophore granular, 

 not dense, usually not covering the cell-wall completely [pi. 24, 



/ 12, 13). 



Exsic. : Phyc. Bor. Am. 619. p. p., Melrose, Mass., March, 

 1894 (F. S. Collins). 



In stagnant water and in brooks, forming light green, floccose 

 masses. 



Connecticut : New Preston, September (495). 



New York : Botanical Garden, May (376B) ; Central Park, 

 April (320). 



New Jersey: Grantwood, April (530), May (437); Edge- 

 water, March (66 C). 



The material collected in Connecticut (495) furnished interest- 

 ing studies of the zoospores. The cell-wall appeared to swell 

 and soften, and exhibited little of the definite pulling apart in sec- 

 tions usually considered characteristic of this genus. The zoospores, 

 mostly one in a cell, were in active movement some time before 

 they were released ; to set them free the cell-wall seemed to dis- 

 solve into mucus and completely to disappear. The zoospores 

 had two cilia and a red eye-spot : this is contrary to the generally 

 received description, in which it is said that the zoospores have 

 four cilia and no eye-spot. It is hard to believe that these were 

 microzoospores or gametes, formed only one in a cell as they 

 were. 



The above characterization of this species illustrates what may 

 be regarded as a legitimate enlargement of an original description. 

 Specimens have been found which correspond exactly to the de- 

 scription and type material of Kutzing, having cells whose length 

 is about equal to the diameter ; by means of continued observa- 

 tion, it is discovered that such cells may grow to be three times as 

 long as the diameter (or even four times as long according to 

 Wille). By similar study the measurement of the diameter has 

 been increased from 7.5 p. to 9.5 p. 



8. Microspora tumidula sp. nov. 



Filaments forming dull green floccose masses or long skeins ; 

 cells nearly cylindrical but always slightly constricted at the dis- 

 sepiments, 6.7-9.5 p (generally about 7.5 //) in diameter, 1-2 times 



