No. 1] CALCAREOUS ALGÆ FROM FUNAFUTI. 5 



at least in part occupy a rather prominent part in bulk. It will 

 be of interest to ascertain, whether any of the above species also 

 are represented here. 



Lithothamnion Philippii Fosl. 

 On some Lith. p. 7. 



f. funafutiensis Fosl. 



Notes p. 3. 



Syn. Lithothamnion decussatum (Solms) Fosl. 1 ) 



I referred 1. c. the present form to L. Philippii, being however 

 in doubt whether it was not, perhaps, to be considered specifically 

 distinct. Afterwards I have had the opportunity of examining more 

 specimens, but still I have not been able to draw any true limit. 



As mentioned 1. c. it elings more firmly to the substratum 

 than the typical form. The conceptacles of sporangia frequently 

 are slightly smaller than in the said form, and they are on a section 

 shown to be more compressed, or a little lower. However, the 

 greatest difference lies in the structure, but even here I have not 

 been able to draw any true limit. In this respect the typical form 

 is rather varying, and so also as regards f. funafutiensis. The 

 perithallic layer shows the same development in both, and in some 

 parts of a crust the cells are much varying in shape and size, in 

 others less, on the whole both forms in this respect corresponding 

 with each other. But on the other hand, the hypothallic layer is 

 as a rule much differing. It is in the typical form frequently to 

 be found distinctly marked and vigorously developed, forming a 

 coaxilate layer composed of cells which are up to 30 p long and 

 18 // broad, frequently however about 18 p. long and 10 p. broad, 

 with thick walls. In f. funafutiensis the hypothallus appears as 

 a rule to be much reduced, on a section frequently showing a very 



!) I still keep the name Lithothamnion Philippii to avoid confusion with the 

 plant described under the name of L. decussatum by Ellis & Solander 

 and Philippi. 



