I 



F. Borgesen: Rhodophyceæ of the Danish W. Indies. 123 



leaf-like thin part of the thallus. This is much ramified. The 

 branches or proliferations issue along the margin of the frond 

 and these are again branched in the same way several times; 

 the ultimate ramifications in my specimens are long and narrow 

 and taper evenly against the summit. 



A transverse section shows that the medullary layer is of a 

 very loose consistency with very much mucilage between the 

 hyphæ-like filaments of which it consists and between which 

 thicker ones grow out in all directions. The cortical layer con- 

 sists of more roundish cells; these are small, oblong-cylindrical 

 and closely placed at the periphery, large and more loosely ar- 

 ranged innermost. Where the cortical layer passes over into the 

 medullary tissue, scattered starlike cells are found with long 

 thin prolongations, radiating in all directions and fusing together 

 with those from the neighbour cells. 



The specimens found have tetrasporangia. These occur scat- 

 tered over the whole surface and are formed in the cortical layer. 

 They are cruciately divided but often very irregular. They are 

 about 25 — 30^ long. 



This species has been found in several places in the sound between 

 St. Jan and St. Thomas in depth down to 30 — 40 meters. 



Geogr. Distrib. : Mediterranean Sea, warmer parts of the Atlantic 

 Ocean, Canary Island, West Indies etc. 



^g- 



Grateloupia C. As 



1. Grateloupia filicina (Wulf.) Ag. 



Agardh, C, Spec. Alg., p. 223; Systema, p. 241. Greville, Alg. Brit, 

 p. 151, pi. 16. Harvey, Phycol. Brit., pi. G. Kützing, Tab. Phycol., vol. 

 XVII, pi. 22. J. Agardh, Spec. II, p. 180; Epicr. p. 153. 



Fucus filicinus Wulf, in Jacquin, Collectanea, vol. Ill, 1789, p. 157, 

 tab. 15, fig. 2. Turner, Hist. Fucorum, pi. 150. Esper, Icones Fucorum, pi. 67. 



Grateloupia filicina is a littoral alga which commonly grows 

 in more sheltered places in quite shallow water. Bertholü^) 

 points out that most of the species of Grateloupia found in the 

 Gulf of Naples were found in water polluted from the town. In 

 such places Grateloupia filicina also occurs in the West Indies 

 but furthermore it is much common in quite clear water and as 

 it is often fixed to small stones scattered upon the dazzling 

 white coral sand it grows in very intense light. In such places 



1) Berthold, G., Die Cryptonemiaceen des Golfes von Neapel (Fauna 

 und Flora des Golfes von Neapel, XII Monographie, 1884). 



