APPENDIX. 389 



B. LYNGBYE.E. Filaments motionless (?), oscillarioid, 

 inclosed in distinct sheath, tufted or forming strata, with 

 or without enveloping jelly. 



9. Dasygloea. Filaments unbranched. Older sheaths 

 broad, coalescent outside in amorphous gelatinous stratum. 



10. Lyngbya. Filaments elongated, articulated, un- 

 branched ; distinct convoluted cellulose tube ; no gelatin- 

 ous matrix ; articulations close. 



11. Leibleinia. Filaments short, erect, tufted, un- 

 branched ; distinct cellulose coat ; free ; no jelly. 



C. SCYTONEME^;. Filaments articulated, simple, or 

 branched, motionless ; distinct articulations and large in- 

 terstitial (propagative?) cells; sheaths soften and swell, 

 but no gelatinous matrix. 



12. Scytonema. Filaments ceespitose, or, more rarely, 

 fasciculate; a double (lamellar) gelatinous sheath, mostly 

 closed at apex ; branches continuous by lateral growing 

 out of primary filaments, with kneelike base. 



13. Desmonema. Filaments branched, more or less co- 

 herent ; primary branches with connecting cell at base ; 

 secondary branches without cell, annulated. 



14. Arthronema. Filaments articulated, simple, in short 

 lengths, overlapping at their ends in gelatinous sheath. 



15. Petalonema. Filaments branched; outer sheaths of 

 joints expanded upwards and outwards into funnel-shaped 

 bodies, each partly overlapping its successor, forming a 

 common obliquely lamellated and transversely barred 

 gelatinous cylinder. 



16. Calothrix. Filaments closely articulated, tufted, 

 with branches in apposition for some distance, here and 

 there cohering laterally; sheaths firm, often dark-colored. 



17. Tolypothrix. Filaments free, radiantly or fastigi- 

 ately branched, distinctly articulated at bases of branches, 

 which are continuous by ex-current, not in apposition ; 

 sheaths thin, hyaline. 



