334 THE PLANT PHYLA 
Family 7. Coscinodiscaceae. Cells short, ends not 
ribbed.—Coscinodiscus. 
Family 8. Actinodiscaceae. Cells short, ends rib- 
bed.—Actinodiscus, Arachnoidiscus. 
Family 9. Eupodiscaceae. Cells short, ends with 
“‘eves.’’—Eupodiscus, Actinocyclus. 
Family 10. Soleniaceae; 11, Chaetocerotaceae; 12, 
Biddulphiaceae; 13, Euodiaceae; 14, 
Anauliaceae; 15, Rutilariaceae. 
Order NAVICULALES. Flat Diatoms. Filaments. flattened, 
usually fragmented into single cells. 
Family 16. Tabellariaceae. Mostly filaments, cells 
short, rectangular in side view.— | 
Grammatophora, Rhabdonema. 
Family 17. Meridionaceae; 18, Fragilariaceae. 
Family 19. Naviculaceae. Cells single, end with 
central slit.—Navicula, Amphipleura. 
Family 20. Bacillariaceae; 21, Surirellaceae. 
Phylum IV. SIPHONOPHYCEAE. The Tube Algae 
Normally chlorophyll-green filaments composed of one or more 
coenocytes 
Class 7. VAUCHERIOIDEAE. Lower Tube Algae. Fila- 
ments septate or tubular. (Sp. about 
400.) 
Order CLADOPHORALES. The Cladophoras. Septate, the 
segments coenocytic. 
Family 1. Cladophoraceae. Unbranched or branched, 
isogamic.—Cladophora, Pithophora. 
Family 2. Sphaeropleaceae. Unbranched, hetero- 
gamic. Sphaeroplea. 
Order StpHonates. Green Felts. Tubular, irregularly 
branched, chlorophyllose. 
Family 3. Phyllosiphonaceae. Endophytic.—Phyl- 
losiphon. 
Family 4. Codiaceae. Filaments compacted into a 
large plant-body.—Codium, Peni- 
cillus. 
Family 5. Vaucheriaceae. Filaments single, free.— 
Vaucheria. 
