F. Borgesen: Rhodophyceæ of the Danish W.Indies. 309 



that the stichidium should be "sichtbar nachträglich am Kiirz- 

 trieb" does not agree with my observations. 



Nor is his next sentence corroborated upon examination of the 

 plant. Falkenberg maintains here that the stichidia originate from 

 segments of the trichoblasts which, when the trichoblasts are sterile, 

 are never provided with branches. As is seen from figs. 305 and 307 

 a side-branch is always developed from the second segment in the 

 sterile trichoblast, that is to say, just in the same place as that occu- 

 pied by the stichidium in the fertile. According to my view and in 

 contradiction to that of Falkenberg, we arrive at the follow- 

 ing conclusion: that the stichidium has come into existence just 

 through the metamorphosis of the first side-branch issued from the 

 trichoblast and, it cannot therefore be considered as a "novum" 

 found only upon the fertile trichoblast. 



And the occurrence of the antheridial stands just in the same 

 side-branch of the trichoblast as the stichidia (a part of this side- 

 branch being polysiphonous and transformed in the antheridial 

 stand just as in the case of e. g. Polysiphonia), seems to me still more 

 to corroborate the correctness of my view. 



As to the rest of Falkenberg's reflections concerning this sub- 

 ject I am not going to discuss them here. For we have solved the 

 difficulties when we look upon the ramulus as a trichoblast (= 

 Haartrieb Oltmanns). Concerning the trichoblast and its relation 

 to the stem I just want to refer to Rosenvinge's instructive paper: 

 "Sur les organes piliforme des Rhodomelacées" *) and especially 

 to chapter 5 : Formes intermédiaires entre tiges et trichoblastes" and 

 to Oltmanns remarks in Morphologie und Biologie der Algen, Bd. 1, 

 1904, p. 609 and especially p. 709. 



Besides some specimens washed ashore I have only dredged 

 this plant in deep water at about 10 — 15 fathoms in rather open sea 

 and in places where strong currents prevailed. It was found with 

 tetrasporangia in the months January — March and \vith antheridia 

 and cystocarps in the month of March. 



As in the case of so many West Indian algæ this one, too, seems 

 originally to have been described from specimens gathered at the 



*) In Oversigt over det kgl. dan.ske Videnskabernes Selskabs Forhand- 

 linger, 1903, No. 4. 



