2 54 



F. BORGESEN 



ment points being crenulated cell-ends as is the case in M. psendohapteron Gepp 

 and finally by means of true tenacula as found in M. Montagnei Dene. 



Regarding the mode of net formation the present plant quite agreed with 

 M. umbilicatum and therefore I do not hesitate to refer it to this species. It 

 agrees very well with my West Indian specimens and specimens from Cadiz. 



Area of distribution: Mediterranean Sea, West Indies, Red Sea, Australia, 

 Sandwich Islands etc. 



Fam. Codiaceae. 

 Halimeda Lamx. 



H. Opuntia Lamx. forma Reinschii (Hauck) Barton. 



Barton, E. S., The genus Halimeda, p 21. Okamura, K., Icones, vol. Ill, 

 pi. 148. — Halimeda Reinschii Hauck, Ueber einige von I. M. Hildebrandt im Rothen 

 Meere und Indischen Ocean gesammelte Algen. (Hedwigia, 1886, p. 167.) 



The specimens gathered seem to agree very well with the description of 

 HAUCK and the figures of Mrs. Gepp (Miss BARTON). It is a rather small 

 plant forming compact tufts ca. 5 — 6 cm high. The base consists of a short 

 stem from which branches are issued in all directions. The lowermost joints 

 are often broader than long and very thick, followed by a few ones nearly 

 cylindrical and longer than broad, but soon the joints again become shorter, 

 broader than long and trilobed. Higher up again the joint grow smaller, 

 thinner, nearly roundish or ovate and sometimes Hightly trilobed, sometimes not. 

 The midrib is very indistinct. The joints in the lower part are mostly about 

 2 — 3 mm long and 3—4 mm broad, higher up 5—6 mm long and 4—5 mm 

 broad; the uppermost are about 4 mm high and 3 mm broad. 



Area of distribution: Indian Sea, Easter Island. 



Fam. Phyllosiphonaceae. 

 Ostreobium Born, et Flah. 



O. Quekettii Born, et Flah. 



Bornet, E. et Ch. Flahault, Stir quelques plantes vivant dans le teste calc. 

 des Mollusques (Bull. Soc. bot. Fr., T. 36, 1889). 



This species was found in a small Spirorbis, the shell being quite green- 

 coloured by the occurrence of the alga. 



Area of distribution: Europe, North America etc. most likely cosmo- 

 politan. 



