- 132 — 



Okamura's plant seems quite to agree with the West Indian one. 

 It may be hoped that Prof. Oka mura will soon give us a more 

 detailed description of this as yet rather dubious plant. 



Caulerpa Vickersii was found growing entangled among Bry- 

 opsis upon rocks near the surface of the sea in a rather sheltered 

 locality. Found only once: St. Jan, Cruz Bay. It is earlier known 

 from Barbadoes where it was first found by M lle Vickers. 



H al i m ed a. 



As belonging to the Halimeda Tuna group Howe 1 ) has de- 

 scribed a new species Halimeda scabra and further pointed out that 

 Halimeda discoidea Decaisne 2 ) must be considered as a good species 

 well separated from H. Tuna, and of this he has given a detailed de- 

 scription. While Mrs. Gepp in her valuable monograph 3 ) of the genus 

 Halimeda specially laid stress upon the peculiarities of the nodal fila- 

 ments of the central strand as specific characters, Dr. Howe also 

 lays much importance upon the utricles of the peripheral and sub- 

 cortical layers and has here found important characters. 



Halimeda discoidea is according to Howe different from H. 

 Tuna, especially by having the peripheral utricles a little larger, 

 often fused together and in contact above for 1 k — 2 k of their length 

 and therefore only separable with much difficulty after decalcifica- 

 tion, while in H. Tuna the peripheral utricles are smaller, very 

 rarely fused, in contact above for 1 l2o— l ls of their length only and 

 easily separable on decalcification. As to the utricles of the sub- 

 cortical layer, these are subturbinate, obconical orclavate, 35— 110 jm 

 in maximum width in H. Tuna while in H. discoidea they are 

 bullate, varying from broadly funnel-shaped to subglobose 110—215 ^ 

 in maximum width. Further the calcification is slighter in H. dis- 

 coidea than in H. Tuna and finally the nodal filaments of the 

 central strands fuse in twos or threes, are often somewhat co- 

 herent just above the point of fusion in H. Tuna, while in H. dis- 

 coidea they fuse in twos rarely in threes, are not coherent and 



*) M. A. Howe, Phycological studies, III (Bull Torr. bot. Club, 34, p. 494, 1907). 



2 ) J. Decaisne, Sur les Gorallines (Ann. Sei. Nat. II S. 18, p. 102, 1842). 



3 ) E. S. Barton, The Genus Halimeda (Siboga Expeditie, Monogr. LX, 1901). 



