MARINE A.I&M OF BEAUFORT, N. C. 



533 



TABLE 9. SURFACE TEMPERATURE OP WATER AT 5 p. M. OFF LABORATORY WHARF, BEAUFORT, N. C. 



[Expressed in degrees centigrade.] 



" Record available for only part of month. 



ARTIFICIAL KEY TO GENERA. 



A. Color bluish green or blackish, sometimes grayish green or tinted with other colors; single 

 celled or composed of rather short filaments; attached or floating; forming small tufts 

 or rather gelatinous, feltlike masses over considerable areas of the substratum. .1. MYXOPHYCE^E. 

 o. Plants unicellular, cells living singly or a few associated in small ill-defined families 



..CHROOCOCCUS (p. 408). 



oo. Plants multicellular, filamentous 6 - 



b. Filaments tapering at apices into multicellular hairs DICHOTHRIX (p. 416). 



66. Filaments not tapering to Jiairs at apices c - 



c. Filaments unbranched < ^- 



d. Filaments lacking sheath e - 



e. Filaments, multicellular, elongated, straight or curved at the apices, not 



spirally twisted OSCHLATORIA (p. 410). 



ee. Filaments unicellular, short, twisted into a regular, more or less lax spiral 



SPIRULINA (p. 411). 



dd. Filaments with sheath / 



/. Filaments possessing heterocysts MICROCH^TE (p. 414). 



ff. Filaments lacking heterocysts 9- 



g. Filaments composed of several trichomes in each sheath MICROCOLEUS (p. 413) 



gg. Filaments composed of single trichomes in separate sheaths A- 



h. Filaments about i mic. diameter PHORMIDIUM (p. 411). 



hh. Filaments more than i mic. in diameter LYNGBYA (p. 4")- 



