pui-ple ; the surface rather glossy when dry. Substance very rigid, horny, 

 membranaceous, enduring exposure or long immersion in fresh-water without 

 injury. In drying the frond does not adhere to paper. 



The genus Acropeltis was founded by Montagne on a South 

 American species {A. Chilensis), which I have not seen ; to this 

 I formerly added the Austrahan A. phi/llojjjiora, and more re- 

 cently the present elegant plant. That these two Australian 

 species are congenerous I have no doubt, but whether they agree 

 generically with the American is a point as yet undecided. 

 Professor J. Agardh places Bhodi/menia australis, Sond., also in 

 Acropeltis ; but to me that appears to be a genuine species of 

 Khodijmenia. The same author refers the genus to the SplicBro- 

 coccoidece, a position which cannot be determined until the cysto- 

 carpic fruit of the typical species shall be discovered. In placing 

 Acropeltis provisionally in Wiodymeniacece, I am guided more 

 by external habit than by other considerations. Possibly, taking 

 into consideration the fibrous medullary stratum, it would be 

 better placed either in Gelidiacece or in CryptonemiacecB. The 

 structure of the cystocarp must be known before this point be 

 settled. 



Fig. 1. Acropeltis elata, a branch, — the noiural size. 2. Apices, with ne- 

 mathecia. 3. Section tlu'ough a nematheclum. 4. A tetraspore. 5. Trans- 

 verse section through the frond : — these figures variously viagnified. 



