12 RHODOMELACE^. v. 



V. Chondria. Laxly cellular ; the ramuli clubshaped, much attenuated at their 



insertion. Tetraspores lodged in the ramuli. 



VI. Rhodomela. Densely, cellular ; the branches and filiform ranmli opaque, not 



transversely striate. Tetraspores in the terminal, filiform ramuli. 



VII. RTTiPHLiEA. Densely cellular with an articulated axis ; the ramuli (at least) 

 transversely striate or subarticulate. Tetraspores in the terminal, fusiform 

 ramuli. 



*** Frond filiform^ inarticulate^ opaque. Ramuli articulate, longitudinally multistriate. 



VIII. DiGENiA. Hamuli subsimple, quadrifarious, densely imbricated. 



**** Frond filiform, either partially or icholly articulate, or tessellated (i. e. the surface 

 cells coequal, arranged in transverse rows.) 



IX. PoLTSiPHONiA. Frond, at least the younger parts, obviously articulate ; the 

 articulations longitudinally two or many-striate. 



X. BosTRYCHiA. Frond tessellated with quadrate or oblong, purple cells. 



***** Frond filiform or compressed, inarticidate or subarticulate, beset with byssoid, 

 single-tubed, articulate ramelli, which bear the fructification. Stichidia fusiform. 



XI. Dasya. 



I. AMANSIA. Lamour. 



Frond flat, delicately membranaceous, transversely striate, rosy purple, pinna- 

 tifid, midribbed ; the membrane formed of oblong, hexagonal cells, of equal 

 length, arranged in zones a»ross the frond ; the midrib slender, disappearing 

 towards the apices. Conceptacles subglobose, sessile, marginal, containing a tuft of 

 pear-shaped spores. Stichidia marginal, branched, containing a single or double 

 row of tetraspores. Antheridia ovate, stipitate, borne on and about the inrolled 

 apices of the lacinulce. 



A small genus of tropical or sub-tropical Alga^, resembling Delesseria in habit, 

 but readily known, even without fruit, by the structure of the frond, which under 

 a pocket lens appears to be finely striate transversely, and with a glass of greater 

 magnifying power is seen to be composed of hexagonal cells of equal size. The 

 membrane is thin, composed of two strata of cells, with thin walls, containing rosy 

 endochrome. 



