I i 
MYXOPHYCEAE 331 
Family 4. Nostocaceae. Heterocysts intercalary 
prominent.—N ostoc, Cylindrosper 
mum. 
Family 5. Scytonemataceae. Heterocysts intercal- 
ary, not prominent.—Scytonema. 
Family 6. Rivulariaceae. Heterocysts basal.—Rivu- 
laria. 
Family 7. Camptotrichaceae. No _heterocysts.— 
Camptothrix. 
Family 8. Stigonemataceae. Heterocysts intercal- 
ary, not prominent; cells in more than 
one row.—Stigonema. 
Order BacteriaLes. The Bacteria. Not green; typically 
filamentous, but becoming few- or 
one-celled by the solution of the fila- 
ment. Related to the foregoing blue- 
green plants. 
Sub-order TuropacreritA. With sulphur granules in the 
cells. 
Family 9. Beggiatoaceae. Cells in motile filaments, 
colorless.—Beggiatoa. 
Family 10. Rhodobacteriaceae. Cells single, or in 
colonies; red, rose or violet colored.— 
Chromatium. 
Sub-order Evsacterra. Without sulphur granules in the 
cells. 
Family 11. Phycobacteriaceae. Cells in straight, 
motionless filaments.—Crenothrix, 
Sphaerotilus. 
Family 12. Spirillaceae. Cells in spirally coiled, mo- 
tile filaments.—Spirillum, Microspira, 
Spirochaete. 
Family 13. Bacteriaceae. Cells mostly single, elon- 
gated, straight.—Bacterium (no flag- 
ella), Bacillus (surface - flagella), 
Pseudomonas (polar flagella). 
Family 14. Myxobacteriaceae. Cells elongated, with- 
out flagella, growing in definite, slimy 
colonies.—Chondromyces. 
Family 15. Coccaceae. Cells mostly single, spherical. 
—Micrococcus, Streptococcus, Sar- 
cina. 
