558 CHAETANGTACEAE. 



Thallus with a compact cortex, free assimilatory filaments 

 wholly or mostly wanting. 

 Thallus terete or nearly so. at least when living. 



Thallus continuous or only occasionally and irregularly 

 articulate: only sexual reproduction known. 

 Thallus slightly or not all annulate, the surface com- 

 monly more or less roughened in lower parts by 

 free assimilatory filaments. 5. G. squaUda. 



Thallus distinctly annulate or transversely rugose, 



glabrous or nearly so. 6. G. rugosa. 



Thallus regularly articulate, the surface glabrous and 

 often polished. 

 Main segments terete, 1-2 mm. broad: superficial 

 cells 7 27 m broad, mostly with intercellular spaces, 

 rather easily separating on decalcification : only 

 sexual reproduction known. 7. G. oblongata. 



Main segments often somewhat flattened, 1.54 mm. 

 broad: superficial cells 24 40 broad, mostly with- 

 out intercellular spaces, closely coherent after de- 

 calcification ; sexual and tetrasporic plants differ- 

 ing in structure of cortex. S. G. obtusata-. 

 Thallus distinctly flattened when living, commonly canalic- 

 ulate on drying ; sexual and tetrasporic plants differing 

 in structure of cortex. 9. G. marginata. 



1. Galaxaura subverticillata Kjellm. K. Sv. Vet.-Akad. Handl. 33 1 : 48. pi. 3. 



f. 12-14; pi. 20. f. 17. 1900. 



On rocks at low-water mark or in shallow water, probably the tetrasporic phase 

 of G. rugosa, New Providence. Berry Islands. Gun Cay. North Cat Cay, Salt Cay 

 Bank, Mariguana, and Caicos Islands : Bermuda : Florida ; Cuba ; Jamaica ; Porto 

 Rico ; and American Virgin Islands. Type from St. Croix. 



2. Galaxaura comans Kjellm. K. Sv. Vet.-Akad. Handl. 33 1 : 44. pi. 2. f. 10-18; 



pi. 20. f. 13. 1900. 



Prom low-water mark down to 8 meters (fide Borgesen), perhaps the tetrasporic 

 phase of G. oblongata, Great Bahama, Berry Islands, and Exuma Chain : Cuba ; 

 Jamaica ; Porto Rico ; American Virgin Islands ; and Guadeloupe. Type from Guade- 

 loupe. 



3. Galaxaura lapidescens (Ell. & Sol.) Lamour. Hist. Polyp. 264. 1816. 



Corallina lapidescens Ell. & Sol. Nat. Hist. Zooph. 112. pi. 21. f. g. 1786. 

 Perhaps the tetrasporic phase of G. cylindrical (not yet reported from the 

 Bahamas similar to G. oblongata, but more slender). 



On rocks from low-water mark down to 12 meters (fide Borgesen), Eleuthera : 

 Cuba ; Jamaica ; Porto Rico ; and American Virgin Islands. Type locality unknown. 



4. Galaxaura flagelliformis Kjellm. K. Sv. Vet.-Akad. Handl. 33 1 : 47. pi. 3. f. 



2-11; pi. 20. f. 16. 1900. 

 Probably the tetrasporic phase of G. squalida. 



On exposed rocks at low-water mark or in shallow water. New Providence, Berry 

 Islands, Great Bahama, North Cat Cay, Caicos Islands, and Great Ragged Islands : 

 Bermuda : Florida ; Cuba ; Porto Rico ; and American Virgin Islands. Type from 

 Key West, Florida. 



5. Galaxaura squalida Kjellm. K. Sv. Vet.-Akad. Handl. 33 1 : 55. pi. 6. f. 1-12; 



pi. 20. f. 9. 1900. 



From low-water mark on exposed rocks down to at least 20 m., New Providence, 

 Rose Island, Great Bahama, Watling's Island, Mariguana, Caicos Islands, Castle 

 Island, and Great Ragged Island : Bermuda ; Cuba ; Jamaica ; Porto Rico ; Amer- 

 ican Virgin Islands; and Panama (Colon). Type from St. Croix. 



6. Galaxaura rugosa (Ell. & Sol.) Lamour. Hist. Polyp. 263. 1816. 



Corallina rugosa Ell. & Sol. Nat. Hist. Zooph. 115. pi. 22. f. 3. 1786. 



On rocks near low-water mark, Great Bahama : Cuba ; Jamaica ; Porto Rico ; 

 American Virgin Islands ; and Barbados. Type from Jamaica. 



