EHODOMELACEAE. 573 



3. Amphibia Sertularia (Mont.) :\L A. Howe, comb. nov. 



BostrycJiia Sertularia Mont. Ann. Sci. Xat. Bot. IV. 12: 176. 1S59. 

 Bostrychia scrtularina Kiitz. Tab. Phyc. 15: 9. pi. S5. f. a-c. 1865. " 

 Bostrychia Mazei Crouan; J. Ag. Anal. Alg. Cont. 4: 83. 1897. 



Forming dense mats on rocks near the high-water mark, Rose Island, Great 

 Bahama, Gun Cay, Exuma Chain, and Watling's Ishmd : — liermuda to northern South 

 America. Type from Guiana. 



4. Amphibia pectinata (Kiitz.) M. A. Howe, sp. nov. 



Bostrycliia Vicillardi pecti7iata Kiitz. Tab. Phyc. 15 : 10. pi. 26. f. f-li. 1865. 



Somewhat intermediate between A. tenella and A. Sertularia, being found 

 occasionally in herbaria sometimes under the one specific name and sometimes 

 under the other, but usually, in the West Indies, quite distinct from either 

 species, differing from both in its greater rigidity, in its habit of growth, and 

 in the frequent presence of two rows of "adventitious" ventral branches, show- 

 ing in extreme cases, four ranks of branches of almost equal size and similar 

 development. 



Between the tide-lines on roots of Rhizophora and pneumatophores of Ariccnnia, 

 rarely pendent from the roofs of caverns, Rose Island. Berry Islands, Great Bahama, 

 Bimini, Exuma Chain. Watling's Island, and Mariguana : — Florida and the West 

 Indies generally ; New Caledonia. Type from New Caledonia. 



II. HERPOSIPHONIA Nag. in Schleid. & Xiig. Zeits. Wiss. Bot. 3-4: 238 

 (without mention of species). 1846. Ambronn, Bot. Zeit. 38 : 197. 1880. 



Main axes or long branches with a branch (or branch rudiment) from each node. 



Main axes or long branches strongly curved, with convexity dorsal, giving short 

 branches a somewhat squarrose appearance ; short 

 branches mostly S-10 segments long ; plants mostly 

 4-10 cm. long. 1. //. Pcctcn-Vcneris. 



Main axes or long branches nearly straight or slightly 

 curved w^ith concavity dorsal ; short branches mostly 

 12-30 segments long ; plants mostly 1-3 cm. long. 2. H. tcncUa. 



Main axes or long branches with some of their nodes regu- 

 larly and wholly destitute of branches. 



Plants of straggling, intricate, or repent habit, elongate 

 and subsimple, 0.5—3 cm. lonp- with apex conspicuously 

 rolled towards dorsal surface; main axes 75— 150^ in 

 diameter, even. 3. H. sccunda. 



Plants somewhat bi-tri-pinnate, filiculoid, 2.5-5 cm. long, 

 with apex inconspicuously curved towards dorsal sur- 

 face ; main axes 150-250xt in diameter, swollen at 

 nodes in older parts. 4. H. hipitniata. 



1. Herposiphonla Pecten-Veneris (Harv.) Falkenb. Ehodomel. 315. 1901. 



Polysiplwnia Fcctcn-Veneris var. a, Harv. Ner. Bor.-Am. 2: 46. pi. 16C. 

 1853. 



On PeniciUus, Halimcda, Tlialassia. and various other objects in shallow water. 

 New Providence, Rose Island. Berry Islands. Great Bahama. Bimini, Andros. Ex- 

 uma Chain, Mariguana. Caicos Islands, and Great Ragged Island : — Florida. Type 

 from Key West, Florida. 



2. Herposiphonia teneUa (Ag.) Ambronn, Bot. Zeit. 38: 397. pl.4. f. 9, 11, 13- 



16. 1880. 



Eutchinsia tenella Ag. Sp. Alg. 2: 105. 1828. 

 Polysiphonia tenella J. Ag. Alg. Med. et Adriat. 123. 1842. 

 Polysiphonia Pecten-Veneris var. ^3, Harv. Xer. Bor.-Am. 2: 46. ;>/. 16D. 

 1853. 



On sponges, various algae, roots of lihizoiilKini, etc., from low-water mark down 

 to a depth of at least 20 meters. Berry Islands. Great Bahama. Bimini. Exuma Chain, 

 Watling's Island, Mariguana, and Caicos Islands : — Bermuda and North Carolina to 

 Florida and Barbados ; Mediterranean and Adriatic seas. Type from Sicily. 



