10 Dr. Greville on a new species of Antrophyum. 



conical tubercles, averaging from one-third to one-half of a line 

 in diameter, and less than half their diameter apart, each ra- 

 diatingly sulcated from the apex to the margin, the deep sulci 

 forming between them usually fourteen strongly defined, 

 rough ridges from the apex, each of which is again divided by 

 a short sulcus at its base ; tubercles abruptly defined from the 

 flat surface on which they rest ; intervening surface with mi- 

 nute radiating striae. 



The specimen examined of this, which is one of the rarest 

 ichthyolites of the mountain limestone, is an irregular fragment 

 about 1^ inch long and 5 lines wide ; it is impossible to suggest 

 what part of the body it belonged to. The genus has not been 

 recorded before in the carboniferous limestone. 



From the same locality and in the same collection as the last. 



[To be continued.] 



II. — Notice of a new species o/ Antrophyum. By R. K. Gre- 

 ville, LL.D. &c.* 



[With a Plate.] 



In addition to the two new species of ferns [Oleandra Sibbaldii 

 and Grammitis blechnoides) recently communicated to Professor 

 Balfour by Dr. Sibbald from the island of Tahiti, I have now to 

 submit the description of a third to the Botanical Society. The 

 discovery of this plant is an additional proof how much remains 

 to be done in an island where numerous collections have been 

 made, but which is evidently still rich in undescribed produc- 

 tions. It is to be hoped that Dr. Sibbald will have an opportu- 

 nity of revisiting Tahiti under more favourable circumstances, 

 and that he will add largely to his collections, especially of ferns 

 and mosses. 



The interesting fern which forms the subject of this short no- 

 tice belongs to Antrophyum, a genus having undivided, more or 

 less lanceolate fronds, in which the sori form continuous grooved 

 lines on the simply reticulate venation. Antrophyum is thus 

 nearly allied to Hemionitis, from which, it must be confessed, it 

 scarcely differs, except in the simplicity of the frond, for the 

 grooved sorus is a somewhat variable character. 



There is however another genus, Polytanium of Desvaux, 

 which has been separated on, as it appears to me, more slender 

 grounds. In that genus the sori are not reticulated, but form 



* Read before the Botanical Society of Edinburgh, Ilth May, 1818. 



