120 ERYTHEA. 



forms, however, can be found. The form with cylindrical 

 cells comes very near the description of A. Felisii (Meneg.) 

 Born. & Flah., of which I have not seen specimens. 



Found in May and June, among various algae forming a 

 scum in ditches, Middlesex Fells, Maiden, Mass. To be distrib- 

 uted under No. 207, Phycotheca Boreali-Americana, Collins, 

 Holden & Setchell. 



Anabaena (Sphaerozyga) Bornetiana n. sp. Trichomes 

 straight or somewhat flexuous, VI jx diam.; cells spherical or 

 slightly shorter than their diameter ; heterocysts 13-14// 

 diam., spherical or occasionally oblong, 13-20/i long; spores 

 on each side of the heterocyst, 15-20/t diam., 50-90// long? 

 cylindrical or more commonly tapering slightly from the 

 middle to the rounded ends; epispore smooth, translucent. 



This species somewhat resembles A. catenula, which, 

 however, is in the subgenus Dolichospermum, the spores 

 occupying no definite position in relation to the heterocysts. 

 Moreover the dimensions of A. Bornetiana are nearly double 

 those of A. catenula, and also much exceed those of any 

 hitherto described species in the subgenus Sphc^rozyga. 

 The very regular trichomes, with rather dark blue-green cells 

 and spores, and yellowish translucent heterocysts, make it 

 quite a striking plant, perhaps the handsomest of the genus; 

 I take pleasure in dedicating it to Dr. Edouard Bornet, to 

 whom I am much indebted for assistance in the determina- 

 tion of the Cyanophycese. 



Found in May and June among various algae, forming 

 floating masses or scums in ditches, Middlesex Fells, Maiden 

 and Medford, Mass.; not as a distinct stratum, but as rather 

 scattered filaments. To be distributed under No. 208, 

 Phycotheca Boreali-Americana, Collins, Holden & Setchell. 



Cylindrosdermum ininutissimum n. sp. Trichomes 

 straight, forming a loose aerugineous stratum; vegetative cells 

 cylindrical, very slender, 2-2. 5/i diam., about twice as long; 

 heterocysts cylindric-oblong, 4/< diam., 7-8// long ; spores 

 8-9/f diam., 18-20/f long; epispore (in not quite ripe spores) 

 smooth, translucent. 



