39 



light it often forms large flat expansions, some of the specimens 

 reaching in diameter 12 cm. 



It is a very common species at the shores of the Islands. 

 Geoo:r. Distrib. West Indies. Indian and Pacific Oceans. 



2, Dictyosphseria van Bosseae Borgs. 



BoRGESEN, F., Some Chlorophycese from the Danish West Indies, 

 II (Botanisk Tidsskrift, vol 32, 1912, p. 256). 



Judging from the rather short diagnosis in M°^^ Weber- 

 van Bosse's note I had at first referred my form to D.Versluysi, 

 but after having seen an original specimen of this species which 

 ]y[me Weber has been so very kind as to lend me, I think it is 

 more convenient to consider my plant 

 as a different species even if it shows 

 a great likeness with M™^ Weber's 

 species. Quite in agreement with D. 

 Versliujsi our form is characterized by 

 having a massive thallus and by the 

 presence of the needle-formed processes 

 upon the inner walls of the cells. But 

 my form differs from that from the 

 Malayan Archipelago by its much smaller 

 cells, on an average reaching only about 

 half the size of those in D. Versluysi ; 

 and while the needles in M"^^ Weber's 

 specimens are about 150// long those in my form reach only a 

 length of about 70^, very seldom up to 100/-/. Furthermore, 

 the spines had a rather uneven surface in my specimen whereas 

 they were quite even in D. Versluysi. And judging from the 

 specimen I have seen of this species the spines seem to he present 

 here in all the cells while in my West Indian form cells often 

 occur where they are quite wanting. When to these characters 

 we add the difTerent geographical distribution, I think it justi- 

 fiable to consider our plant as a new species, for which I have 

 taken the liberty of proposing the above name in honour of M'"^ 

 Weber-van Bosse^). 



The cells are about half the size of those in D. faindosa, being 

 on an average about 500 [j- in diameter, but varying, many cells 



Fig;. 23. 

 Dictyosphceria van Bossece 



Borgs. 



Habit of young plant. 



(About 6:1). 



The Ulfa cellulosa Mert. msct. named with a? as a synonym to Valonia 

 favulosa by C. Agardh is this species, judging from a specimen found 

 in the Herbarium of the Botanical Museum, Copenhagen. 



