70 SPECIES OF ALGJE. 



b. " thin, skin-like, expanded gracilis, 306 



b. " dense gelatinous, on partly submerged stones, 



heterotrichum, 307 



104. OSCILLARIA. 



Articulations indistinct (a). 



' about as long as wide (c). 



" one-half " " " " (d) f 



" less than half as long as wide (/). 



a. In hot water from waste steam pipes; diam. 1.8-2.8;*, 



amphibia, 310 



a. Not in hot water (b). 



b. Filaments 1-1.5/4 in diam snbtilissima, 309 



b. 1.8-2.5;* in diam tenerrima, 309 



b. " 2/4 in diam detersa, 310 



f. Diameter 2.8-3;*, rarely 3.5/4 elegans, 310 



c. 2.7-3.2/4 gracillima, 311 



. " 3/4 chlorina, leptotricha, 311 



^. 4.5-5.5/4; on moist ground .... antliaria^ 310 



^/. Floating on hot water; diam. 6-7^1* . . . . . Cortiana, 313 



d. On wet ground (e). 



d. Aquatic (/). 



e. Diameter 4.5-5/4; on shaded mud brevis, 312 



e. " 4-4.7/4; in greenhouses violacea, 311 



<?. " 6-7.75/4; in swampy places limosa, 313 



*. " 7-8yw; wet grounds, Fla chalybea, 314 



f. In large jelly masses; diam. 4-5-6/4 cruenta, 312 



/. Not in distinct jelly masses (g). 



g. Stratum black (h). 



g. " bluish or not black (/). 



h. Filaments with two short cilia at the end; diam. 4.6-6.6/4, 



subfusca y 312 



h. Filaments without cilia; diam. 9-10;* nigra, 315 



/. Diameter 9-11/4; stratum thin anguina 314 



/. 5-5- 8 - 2 /^ tennis, 313; natans, 314 



/. 4-5 /* (zrugineo-coerulea, 311 



j. In brackish or submarine waters (k). 

 j. In sweet waters (/). 



k. Diameter 18-20/4 Grateloupii, 316 



. 12-15/4 littoralis, 317 



