594 DICTTOTACEAE. 



Sargassum pteropus Kiitz. Sp. Alg. 608. 1849. 



Sargassum bahiense Kiitz. loc. cit. 



Sargassum trachyphyllum Kiitz. loc. cit. 609. 



Sargassum polyphyllum Kiitz. loc. cit. Not S. polypTiyllum J. Ag. Sp. 



Alg. 1: 30®. 184S. 

 Carpacanthus polyceratius Kiitz. loc. cit. 624. 

 Carpacanthus spinulosus Kiitz. Tab. Phye. 11: 15. pi. 46 f. II. 1861. 



At low-water mark and in shallow water. New Providence, Rose Island, Great 

 Bahama, North Cat Cay, Watling's Island, Caicos Islands, and Castle Island : — West 

 Indies in general. Type from Cnba. 



The species, as here conceived, shows great variability in form, size, and texture 

 of the leaves, in the size and number of the cryptostomata, in smoothness or rough- 

 ness of the stem, and in the presence or absence of spines on the receptacles, but 

 specific segregations seem impossible. 



10. Sargassum Hystrix J. Ag. Ofv. K. Tet.-Akad. Eorli. 4: 7. 1847. 



Sargassum Hystrix 'buxifolium (Chauv.) J. Ag. Sp. Alg. 1: 322. 1848'. 



Usually found floating or washed ashore, but also attached, in about 3 m. of 

 water. New Providence, Joulter's Cay, Ahaco, Berry Islands, and Exuma Chain : — 

 o£E North Carolina, Isle of Pines, and Mexico. Type from the Campeehe Banks. 



A form with large oblong entire or subentire leaves is var. huxifoliitm. 



Tamily 7. DICTYOTACEAE. 

 1. ZONAKIA Drap.; Ag. Syn. Alg. Seand. xx. 1817. 

 Stypopodium Kiitz. Linnaea 17: 97. 1843. 

 Phtcopteris Kiitz. loc. cit. 



Gymnosorus J. Ag. Anal. Alg. Coat. 1: 9. 1894. Not Gymnosorus Trevis. 

 Alg. Cocc. 108'. 1848. 



Thallus obscurely zonate, brownish both when living and on drying, 2-7 cm. long, 

 at iirst more or less prostrate or subrepent and semiorbicular or flabelliform, later 

 free except at the broad or occasionally substlpitate base and 

 showing few entire or sparingly laciniate flabelllformi lobes. 1. Z. variegata. 



Thallus distinctly zonate, more or less brownish blue-green and 

 iridescent when living, commonly blackening on drying, mostly 

 7-30 cm. long, erect, stipitate or substlpitate, repeatedly cleft 

 or lobed, the lobes cuneate, cuneate-oblong, cuneate-flabelliform, 

 or linear, occasionally lacerate or fimbriate-laciniate. 2. Z. zonalls. 



1. Zonaria variegata (Lamour.) Ag. loc. cit. 



Dictyota variegata Lamour. Nouv. Bull. Sci. Soo. Philom. 1: 331. 1809. 



Zonaria coUaris Ag. S-p. Alg. 127. 1820. 



Padina variegata GaUl. in Diet. Sei. Nat. 53: 371. 1828. 



Spatoglossum variegatum Kiitz. Sp. Alg. 560. 1849. 



Gymnosorus variegatus J. Ag. Anal. Alg. Cont. 1: 11. 1894. 



Gymnosorus collaris J. Ag. loo. cit. 



On calcareous algae, rocks, old corals, Gorgoniidae, roots of BMsopTiora, shells 

 of conchs, etc., common from low-water mark down to a depth of several meters ; 

 often found washed ashore. New Providence, Hose Island, Andros, Berry Islands, 

 Great Bahama, Gun Cay, Abaco, Green Cay, Exuma Chain, Watling's Island, Atwood 

 Cay, Mariguana, Caicos Islands, and Great Ragged Island : — Bermuda and Florida 

 to Brazil ; Canary Islands ; Philippines ; widely distributed in the warmer seas. 

 Type from the " Antilles." Prostrate or subrepent forms are to be distinguished 

 carefully from Aglcmisoma canariensis. 



2. Zonaria zonsilis (Lamour.) M. A. Howe, in Britton, PI. Bermuda 507. 1918. 



Fucus zonalis Lamour. Diss. 38. pi. S5. f. 1. 1805. 



Dictyota zonata Lamour. Nouv. Bull. Sci. Soc. Philom. 1: 331. 1809. 



Zonaria lobata Ag. Syst. Alg. 265. 1824. 



Stypopodium lobatum Kiitz. Tab. Phye. 9: 25. pi. 63. f. I. 1859. 



On rocks, etc., in shallow water. In moderately exposed positions. New Provi- 

 dence, Berry Islands, South Biminl, Gun Cay, Exuma Chain, and Atwood Cay ; 

 Bermuda to Brazil ; Canary Islands. Type from Santo Domingo. 



