No. 3] NEW OR CRITICAL CALCAREOUS ALGÆ. 11 



species is 1. c. p. 410 and p. 414 divided into three differend spe- 

 ■cies, in part with reference to the same figures, and one of the 

 latter recorded under the name of -L. falsellum. 



I do not think to be in the wrong in referring some speci- 

 mens from the Cape of Good Hope to the above species, which 

 -appears in two different forms. The one I consider the typical 

 form of the species, and the otlier I propose to name f. plicata. 

 This form differs from f. genuina the branches being more or 

 less folded or plicate, regularly fastigiate and rather confluent with 

 each other. It is a characteristic form and I have not seen an}^ 

 true transition to f. genuina, but it coincides with this as to the 

 conceptacles of sporangia as well as in structure. However, in 

 both forms I found the conceptacles intei-sected with 30—40 muci- 

 ferous canals, and as regards the structure the measures given by 

 Heydrich do not fully correspond with the general size of the 

 cells in the specimens examined by me. 



The species is hilherto only known from the Cape of Good Hope. 



Lithothamnion sjmanablastum Heydr. 

 in Ber. d. deutsch. bot. Ges. Bd 15. Pag. 54. 



f. consjjersa Fosl. mscr. 



Lithothamnion s\'nanablastum He3'dr. I. c. 



f. speciosa Fosl. mscr. 



This species appears like several other Lithothamnia to be 

 much varying. In f. conspersa the surface is often more or less 

 uneven, partly on account of the substratum partly owing to 

 overgrown extraneous objects, but old specimens also produce 

 wartlike or small branchlike excrescences. Sometimes more crusts 

 grow over each other. In parts of old specimens I h^-ve seen up 

 to three crusts, each loosely clinging to the subjacent and but here 

 and there anastomosing. Otherwise this form elings rather firml^' 

 to the substratum especially in a young state. 



The form speciosa is perhaps to be considered onlj^ a local 

 form of the species, but, on the other hand, at first sight so re- 

 markable that it makes the impression of a separate species, and 



