18 M. FOSLTE. [1900 



rather numerous short side-branches. The branches are in the 

 lower part occasionally a little thicker than in O. spectabile, up 

 to about 3 mm., and sometimes a little more attenuating upwards. 

 In structure it almost fully coincides with the latter, however here 

 and there with a little longer cells and thinner walls. The speci- 

 men appears at any rate to be closely allied to the spedes in 

 question. It bears a solitary conical conceptacle about 800 <j. in 

 diameter at the base. 



A steril specimen from Mauritius, herb. Pro f. Ja din, no. 549, 

 also represents a form closely related to 0. spectabile, the above 

 f. brevifulta, but also this being steril I do not know whether it 

 perhaps is a separate species. It surrounds a piece of a branch 

 of a Coral, forming a somewhat irregular nodule about 7 by 4 

 cm. It is branched in the same manner as f. typica, the branches 

 of about the same thickness, but less crowded, in part rather 

 diverging, rather curved and knotty. 



The latter form in the main coincides in structure with f. 

 typica, only the cells of the pith layer frequently being slightly 

 shorter and the perithallic layer not so vigorously developed, some- 

 times with a thin layer of subhyaline cells. 



Two other and small specimens labelled Mauritius? — herb. 

 Far lo w, no. XXXII — XXXIII, on the one side stand near to the 

 above mentioned small specimen from Bermuda, herb. Far lo w, 

 no. XIX, and on the other hand closely related to f. brevifulta 

 are probably to be referred to the latter. 



The typical form of the species in question is with certainty 

 only known from Bermuda, and f. brevifulta only known from 

 Mauritius. 



Subgen. Herpolithon Fosl. mscr. 



Thallus crustlike. Conceptacles of sporangia subimmersed with 

 elongated tip or constricted above the middle, the latter part fre- 

 quently at length falling away. Conceptacles growing down in to 

 the frond. 



Type: G. Notarisii (Du f.) Fosl. 



