— 192 - 



star-like cells, which again are placed upon the membrane cells (Fig. 12 

 A,B, E), while the gland cells in every case in the five species QiChrysy- 

 menia I have found in the West Indies, are placed directly on the 

 membrane cells.^) By means of these characters our plant may 

 easily be distinguished from the genus Chrysymenia^ although on 

 the other hand it agrees very much with the latter in the whole 

 structure of the thallus and in the fact that the tetraspores are 

 dispersed over the whole surface of the thallus. From the other 

 genera with septa: Champia and Chylocladia, our plant is easily 

 separated, as these genera have quite a different apical growth, 

 and by the presence of the characteristic longitudinal filaments 

 which bear the glands. The genus Lomentaria is quite in the same 

 way well separated from it by the presence of the longitudinal 

 filaments and also by the fact that the tetrasporangia occur in 

 immersed groups. Finally the genus Bindera differs by having no 

 diaphragms and by having the tetrasporangia arranged in groups. 

 On the basis of these facts I therefore believe that our plant 

 may be considered as a representative of a new genus to which I 

 shall propose the name Coelarthrum, with the hitherto only known 

 species: Coelarthrum Albertisii (Piccone) nob. 



Coelarthrum ^) nov. gen. 



Frons tereticuscula, articulata, dichotome ramosa, cava, sed 

 ad geniculas diaphragmatibus instructa. Membrana intus ex cellulis 

 majoribus oblongis rotundatis, extra cellulis corticalibus minoribus 

 rotundatis composita. In interiore fronde ad cavitatem amplam 

 eius spectantes cellulse glandulosge sphsericae ex cellulis irregulariter 

 stelliformibus procrescentes occurrunt. Tetrasporangia in strato cor- 

 ticali sparsa, cruciatim divisa. Gystocarpia per totam frondem sine 

 ordine sparsa, hemisphserica prominentia, poro apicali minore 

 aperta. 



C. Albertisii (Piccone) nob. 



Chylocladia Albertisii Piccone, A., Alghe in "Grociera del Corsaro 

 alle Isole Maderae Canarie del Capitano Enrico d'Albertis", p. 37, 

 tab. fig. 3— o.Genova 2884. (Fig. 11 and 12.) 



^) In Chrysymenia ventricosa I have however as mentioned above once found 

 some glands placed not immediately upon the wall of the large membrane 

 cell but on a small roundish cell and Prof. Kuckuck has figured a similar 

 case in his not yet published paper. 



^) derivated from xddog = hole and ^dp^pov = joint. 



