211 



much likeness to Dictyota Bartayresiana. M™^ Weber has also 

 suggested (in "Algues du Siboga", p. 182) that the present plant 

 may perhaps be nothing more than a form of this species. 



The specimens were found in shallow water and in sheltered 

 places only. Most of them were lying loose upon the bottom. 



It has been collected, St. Croix: Behind Long Reef, Salt River. 

 Geogr. Distrib. West Indies. 



5. Dictyota Indica Sond. 



SoNDER in KiJTziNG, Tab. Phycol., vol. IX, p. 8, tab. 17, fig. I. 

 VicKERS, A., Phycologia Barbadensis, pi. XVIII. 



The specimens referred to this species were much like the 

 figure of M'^*' ViCKERS (1. c). They are repeatedly dichotomously 

 ramified and somewhat twisted. 



The tetrasporangia and oogonia occur upon both sides of the 

 frond, the first-mentioned in small scattered groups, mostly two 

 to three together. 



In the open sea the specimens are rather rigid, in sheltered 

 places more flabby. 



When found in the open sea it is usually in deeper water 

 down to a depth of about 10 — 12 meters, when found in sheltered 

 places it occurs only in shallow water. 



St. Croix: off Frederiksted, Longford, near Buck Island, Lt. Princess, 

 Christiansteds Lagoon; St. Thomas: Bovoni Lagoon; St. Jan: Reef Bay. 

 Geogr. Distrib. West Indies. 



6. Dictyota ciliata J. Ag. 



J. Agardh, In Historiam Alg. Symbolaj ("Linnsea", XV, 1841, p. 5). 

 J. Agardh, Spec. Alg., I, p. 23. J. Agardh, Till Algernes Systematik, V, 

 p. 94. J. Agardh, Analecta Algologica, Contin. I, p. 75. Harvey, Nereis 

 Bor.-Am., p. 110, pi. VIII A. F. Kutzing, Tab. Phycol., vol. IX, pi. 27. 

 A. ViCKERS, Phycol. Barbad., pi. XVII. 



This species is as well known characterized by the presence 

 of small acute teeth along the margin of the thallus. When it 

 is growing in sheltered places it has a tendency to become proli- 

 ferous along the margins as shown in the one figure of M'^'' Vickers. 



The tetrasporangia occur in small scattered groups on both 

 sides of the frond and contain a few, or up to ten sporangia in 

 each group. The oogonia form small roundish sori also upon 

 both sides of the thallus. And the same is the case with the 

 distribution o^" the antheridia which form rather large, oblong to 

 oval groups. The single antheridium is about 50// long and 30/^ 



