No. 6] NEW MELOBESIEAE. 19 



G. elatocarpum Fosl. 



New or crit. calc. Alg. p. 23. 



f. australasica Fosl. mscr. 



Thallus more smooth than in the typical form, and the cells 

 smaller. 



This form assumes suborbicular crusts on a plain substratum, 

 or almost surrounds small stones. It is up to about 2 mm. thick, 

 here and there with very small excrescences. Also in structure it 

 is closely related to the typical form, but the cells are frequently 

 a little smaller than in the latter. The conceptacles look small 

 and not well marked after the upper part has fallen away. 



The present form partly approaches certain forms of Gr. Notarisii 

 partly rather resembles Lithothamnion funafutiense f. pmyurascens 

 in habit. On the other hand, Cf. Notarisii sometimes may be difficult 

 to separate from specimens of Lithothamnion Philippii not furnished 

 with conceptacles of sporangia, and even in structure the limits 

 are not always easy to draw. The conceptacles of sporangia in 

 the genus Ooniolithon in certam stages rather approach in shape 

 those of cystocarps in Lithothamnion, and, therefore, such speci- 

 mens of the said species may also be confounded without closer 

 examination. 



The typical form of the present species is only known from 

 the south coast of Africa; f. australasica has been picked up from 

 a depth of 3 — 5 fathoms in Western port, Victoria, and kindly 

 communicated to me by Mr. J. Gabriel. 



G. Borgesenii Fosl. mscr. 



Thallus forming irregular, 2 — 5 mm. thick crusts on Corals, 

 with wartlike or irregular excresences frequently 3 — 5 mm. in dia- 

 meter. Conceptacles (of sporangia?) subhemispheric with a central 

 pore, 300 — 400 fi in diameter. 



The crust develops more or less numerous, smaller or larger, 

 wartlike or irregular excresences which] sometimes are crowded 

 and anastomosing. However, these excrescences not seldom are 

 due partly to the uneveness of the substratum partly to their co- 



