382 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



This is a common species along the shores of the islands. 

 It occurs in shallow water and mostly in more sheltered places, 



but it is also found in somewhat 

 exposed localities. 



In the last mentioned places 

 where the light, too, was strong 

 some specimens were gathered which 

 were covered quite densely with 

 long, unicellular, hyaline hairs. 

 These hairs serve most probably as 

 a protection against strong light*) 

 being present in so many littoral 

 algæ and non existing or less deve- 

 loped in those from deep water. 

 That the hairs, on the other hand, 

 also may serve as absorbing organs 

 of nutriments, is very likely**). 



Hypnea mnscijormis is often an 

 epiphyte upon larger algæ and 

 occurs commonly entangled among 

 other algæ to which it fixes itself 

 by means of the tendrils. 



Specimens with tetrasporangia 

 were found in the month of February. 



St. Croix: Christianssted's harbour, 

 Christianssted's Lagoon, Lt. Princess, 

 White Bay, Casavagarden etc. St. Tho- 

 mas: Store Nordsidebugt. St. Jan: Coral 

 Bay, Cruz Bay. 



Geogr. Distrib.: Seems to occur 

 in all warmer seas. 



Fig. 367. Hypnea cornuta 



(Lamour.) J. Ag. 



Part of a plant. (About 3:1). 



2. Hypnea cornuta (Lamour.) J. Ag. 



J. Agardh, Spec. Alg., vol. II, p. 449; Epicr. p. 563. 



Gigartina cornuta Lamour. mscr. 



Chondroclonium cornutum Kütz., Spec. Alg., p. 741. 



*) Vide Berthold, G., Beiträge zur Morphologie und Physiologie der 

 Meeresalgen. Pringsh. Jahrb. f. wiss. Bot., Bd. 13, 1882 p. 675. 



**) Rosenvinge, L. Kolderup: Remarks on the hyaline unicellular hairs 

 of the Florideæ (Biol. Arbejder tilegnede Euo. Warming, København 1911). 



