F. Borgesen: Phæophyceæ of the Danish W. Indies. 



25 



especially the innermost, are lengthened, often nearly cylindrical. 

 Here occur also now and then a few hyphal filaments running 

 along the walls of the large cells. 



The surface cells each contain a small, irregularly lobed, flat 

 chromatophore (Fig. 15 /). The large cells in the interior seem 

 to be nearly or quite colourless. 



Hairs, isolated or a few together, occur scattered over the 

 whole surface of the thallus (Fig. 16). They are found in the 

 sterile as also in the fertile part of the thallus but most commonly 

 in the latter, where they are present sometimes in the middle 

 sometimes in the periphery of the sori and most often isolated 

 though occasionally two-three together. 



The diameter of the hairs is about 

 8— 9 p. 



The plurilocular sporangia occur 

 in irregularly formed groups spread 

 over the whole surface of the frond 

 (Fig. 17). The sporangia are devel- 

 oped from the surface cells. They are 

 cylindrical, or often somewhat clavate 

 (Fig. 16) and reach a length of 20 p — 

 40// and even more and a breadth of 

 5 — 12 ft. Paraphyses are wanting. At 

 the edges of the sori the sporangia 

 become gradually shorter and pass 

 evenly into the sterile surface cells. A 

 small depression is sometimes found in 

 the middle of the sori but not always. 



I had no sooner started to exa- 

 mine this plant than I began to realize that I was probably dealing 

 with a new genus. The plant appeared related to the family 

 Encoeliaceæ and especially to the group Scytosiphoneæ, comp. Kjell- 

 man in "Die natürl. Pflanzenfam.", 1. Theil, 2. Abt., p. 197. 

 Certain difficulties arise in referring this plant to this group e. g. 

 its ramification. 1 therefore asked the opinion of Professor Kuck- 

 uck and he most kindly gave me very useful information. 



Professor Kuckuck agreed with me that my plant was a 

 representative of a new genus and that it was nearly related to 

 Scytosiphon. He directed my attention to some species till now 

 usually referred to Asperococcus and to Chnoospora fastigiata and 

 most kindly sent me drawings as well as preparations of these 

 for comparison. 



Fig. 17. Rosenvingca Sanctæ 



Cruris nov. spec. 

 Surface view of a plant show- 

 ing the irregular groups of 

 plurilocular sporangia. 

 (About 20 : 1). 



