290 PERCY SLADEN TRUST EXPEDITION 
A small fragment, attached to Gelidiopsis variabilis. In the ‘Siboga” paper I hope to 
point out that Schmitz was perfectly right, when he supposed that Roschera africana, 
Sonder, and Tolypiocladia glomerulata belonged to the same genus. I have therefore 
made use in this paper of Sonder’s older generic name. 
Herposrpnonta, Naegeli. 
1. HerPosiPHONIA PROREPENS (Harv.), Schm. 
Harvey, Phycol. Australica, tab. 185 (B). 
Chagos Archipelago. 
Distribution. Algoa Bay ; Western Australia. 
After describing the present plant, Harvey adds: ‘“‘ This alga was first described from 
Algoa Bay, where it occurs on corallines. The Australian plant is more slender, with 
fewer tubes, but otherwise the same.” The Herposiphonia on Dasyopsis Geppii has 
8 pericentral tubes; it stands therefore nearest to Harvey’s Australian form. My 
material is too scanty to make out whether these forms are specifically distinct from 
the Algoa plant, as some authors have thought probable. 
OxigocLtADuS, Weber-van Bosse. 
1. Oxtcoctapus PRarinit*, n. sp. (Plate 18. fig. 31.) 
Thallo filiformi repente, ramis normaliter dorsaliter exeuntibus, erectis, endogenis, 
ramulos unilaterales ferentibus. Filo constante ex uno ordine cellularum centrali 
et ex quatuor ordinibus cellularum pericentralibus. Trichoblasti desunt. Filis 
latis 120-200 pu, ramulis 12-80 ». Organis fructificationis ignotis. Rhizoidis 
unicellularibus. 
Coetivy, reef, on Dasyopsis aperta; in alcohol. 
The alga that I have named Oligocladus Prainii belongs to the subfamily of the 
Herposiphonez, and is very nearly allied to the new genus Oligocladus, provisionally 
described in ‘Annales du Jardin botanique de Buitenzorg,” 1910, p.31. The specimens 
were found growing among the penicilli of Dasyopsis aperta and are barren; the 
determination is therefore not quite certain, but in anatomical structure these algze so 
closely resemble O. Boldinghii, Web. v. B., that I feel almost sure that they belong 
to this genus. I may also add, that in a few long branches I have seen a con- 
densation of protoplasm in two cells of each segment. This reminded me of the 
two sporangia in each segment in Oligocladus Boldinghi, but in the present case I 
could not detect the slightest trace of division in the protoplasm. They were, however, 
too young, and I must leave it to future investigators to settle the question. 
O. Praini is a creeping filamentous alga with four pericentral cells, dorsally placed, 
endogenous branches, and unicellular exogenous ventral rhizoids. Thus far it is lke 
O. Goldinghw. It differs from this alga in having no trichoblasts, but a naked, straight 
* Named in honour of Sir David Prain, in remembrance of a lovely walk in the Botanical Gardens at 
Calcutta. 
