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



occurring in irregular rows. These specimens certainly approach 

 the form described by Berthold in his "Bangiaceæ" p. 26 as 

 Goniotrichum dichotomum and found in the Gulf of Naples, but 

 he found up to eight cells in a cross section of the thallus while, 

 as mentioned above, I found 2—4 only. Hauck refers Berthold's 

 plant to Goniotrichum Cornu Cervi (Reinsch) Hauck i) but in 

 this species there are many more cells together in the filaments 

 at the same level. 



My plant evidently comes very near to the form from the 

 coast of Peru mentioned by Howe 1. c. 



In the specimens from the Danish waters which are figured 

 and described by Rosenvinge we find now and then more than 

 a single cell at the same level. According to Rosenvinge's 

 statement this was caused in the specimens examined by him 

 not by longitudinal walls but by displacement of the cells. In 

 addition to this way of obtaining several cells in the filaments 

 the multiplication of the cells in my plants is certainly also due 

 to longitudinal division of the cells (comp. fig. 2 d). 



The cells contain a starlike chromatophore with a central 

 pyrenoid. In the filaments consisting of a single row of cells 

 these are mostly short, often only a fourth part of their diameter; 

 the most common is that about half their length, more rarely they 

 are about as long as broad. The diameter of the cells is about 12^^. 



In the filaments on the other hand consisting of several 

 cells these are most often about as long as broad and by mutual 

 pressure of irregular polygonal shape. 



The ramification is described in detail by Rosenvinge; it 

 reminds one as is well-known of the so-named false branching of 

 the Scytonemataceæ. 



Concerning the reproduction Rosenvinge has not made any 

 observation and I have not succeeded in finding anything in my 

 material. 



The plant is found partly upon other algæ partly upon 

 different substrata e. g. old pieces of tree etc. It seems to be 

 a common plant at the islands. 



St. Thomas: French Wharf. St. Jan: Near America Hill. St. Croix: 

 Christianssted, Lt. Princess, Frederikssted and other places. 



Geogr. Distrib. Europe, Mediterranean Sea, Maroc, Peru. 



1) Hauck, F., Meeresalgen, p. 17. This species was first described by 

 Reinsch in "Contributiones", vol. I, 1875, p. 40, pi. XV and here 

 called Stylonema Cornu Cervi. 



