124 



WEBEE-VAN BOSSE ON THE 



habit, having a well defined stem and regularly placed lateral branches, whereas Endo- 

 dphonia has no definite stem nor regular ramification. Anatomically the genus is 

 characterized by its four big pericentral cells (fig. 30, p.c,\ surrounded by several layers 

 of cortical cells which are always much smaller. In Endosiphonia the four pericentral 



cells are surrounded by cells of the same size. 



The stem of FseudendosijjJionia is attached to small flat stones or particles of rock 

 by means of small rhizoids and around it stand four branches with a divergence of I ; 

 they take their origin from the central cell and are therefore endogenous ; the lateral 

 ones are of unlimited growth (Langtriebe), the dorsal and ventral ones remain short 

 (Kurztriebe). The lateral branches have the same development as the principal stem, 

 but their side-branches remain at first short and give the plant a thorny appearance 

 that strongly reminds one of Endosiphonia. At the top of some branches there are 

 luxuriously developed trichoblasts ("leaves," Ealkenberg), but on most they had fallen 

 ofT, probably because they have so many side-branches and such large cells. 



The stichidia bear a great resemblance to those of Endosiphonia, particularly to 

 E. clavigera, for they are placed irregularly on the stem and branches (PI. 13. fig. 14) 

 and not in the axils of the latter. They spring from peripheral cells and have a mono- 

 siphonons pedicel, but this bears branches, which is not the case with E. clavigera. The 

 stichidium itself was bare in all the specimens examined, but I think it likely that the 

 branches of the pedicel may develop further stichidia. I noted at the top of these 

 branches some divided cells that I thought would develop into stichidia, but no later 

 stages were observed. The cells covering the tetraspores in the stichidium are not 

 horizontally disposed as in Endosiphonia but are arranged more or less obliquely. It is 

 not certain, however, how far this may change as the sporangium attains maturity. 

 This alga differs from the genus Endosiphonia by its habit and anatomical structure, 

 and though nearly related to it, I believe I am justified, on account of these differences, 

 in describing it as a new genus. 



I have great pleasure in dedicating this interesting species to Mr. J. Stanley 



Gardiner. 



Cladhtmenia, Hooker et Harvey. 



1. Cladhymenia oblongifolia, Hook, et Harv. (Plate 12. fig. 7.) 



Hooker et Harvey, Alg. Nov. Zel. no. 70. 



De Toiii, Syll. Alg. vol. iv. sect. iii. 1903, p. 850. 



Amirante, 25 fms. ; dry specimens and in alcohol. 

 Distribution. New Zealand. 



The specimens from Amirante are small (PI. 12. fig. 7) but identical with some that I 

 received from Prof. J. Agardh from New Zealand under the name of Oladhymenia 



oblongifoliay var. I think that the small size of the Amirante specimens may be 

 accounted for by the great depth from wliich they come. 



