B38 Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



reproductive organs among the specimens collected, these being quite 



sterile. 



If we now ask to which of the forms of Rhodomelaceæ our plant 

 come nearest this question is, of course, difficult to answer as long 

 as we do not know its reproductive organs. We must surely look for 

 its nearest relatives amongst the dorsiventral forms of the Rhodo- 

 melaceæ, even if it does not seem to be so very closely related to any 

 of the known forms. The arrangement of its branchlets in two rows 

 on the dorsal side of the stem bears a resemblance to that in Clif- 

 tonia. We ought also to compare it with forms of Bostrijchia and 



related genera. 



It was found in very small quantities intermingled between 

 the Callithamnion spec, mentioned above on p. 220 — 1. 



Only dredged once in deep sea at a depth of about 20 fathoms. 



St. Thomas. In the sea to the west of Water Island: off Great 

 Crum Bay. 



Fam. 3. Delesseriaceæ. 



Siibfani. 1. Sarconemieæ. 

 Tænioma J. Ag. 



1. Tænioma perpusillum J. Ag. 



Agardh, J., Nya alger från Mexico (Ölvers. k. Vet.-Akad. Forhandl., 

 1847); Spec. Alg., vol. II, p. 3, p. 1257. 



Tænioma macrourum Thuret in Bornet et Thuret, Notes algolog., 

 fasc. 1, pag. 69, pi. XXV. Falkenberg, P., Rhodomelaceen, p. 709, pi. 

 15, figs. 21—29. 



Polysiphonia nana Kütz., Tab. phycol., vol. XIII, p. 10, pi. 29. 



Already in 'Notes algologiques" Thuret expressed his doubt 

 as to the specific difference between the Mediterranean form and the 

 Pacific one. In 'Les Algues de P. K. A. Schousboe" Bornet, after 

 having examined specimens of Tænioma perpusillum, arrives at the 

 conclusion that the two species cannot be distinguished from each 

 others. On the other hand Falkenberg, I. c. p. 709, maintains the 

 difference between the two plants basing his conclusion especially 

 upon the non-existence in Tænioma perpusillum of the long monosi- 

 phonous hair-like filaments which crown the summits of the branch- 

 lets in Tænioma macrourum. iNot having had any specimens of the 



1 



