scattered or fasciculate, filiform, attenuated at base, tapering and acute, 

 spreading or divaricate. All parts of the frond arc opaque, coated with a 

 thick layer of minute cellules; but, under a pocket-lens, the lesser branches 

 and ramuli arc very obviously striate transversely. Ceranddia ovate, soli- 

 tary, scattered, on longish ])cdicels, rarely subsessile, opaque and thick- 

 walled. SticJiidla shortly lanceohite or spindle-shaped, in dense tufts on 

 the sides of the ramuli and lesser branches, containing a double row of tetra- 

 spores. Colour a very dark brownish-purple, becoming black in drying. 

 Substance tough and rigid. Under strong pressure the young frond will 

 adhere to paper ; the older does not adhere. 



A very large, tough, and coarse-growing species, a native pro- 

 bably of deep water, from which branches are more frequently 

 cast up than perfect fronds. I have seen several branches which 

 must have been torn from fronds that were at least two feet 

 high, and perhaps of greater height ; a very large size for one of 

 the filiform Bhodomelacea . 



This Alga was originally described by Sonder as a species of 

 BJiodomela ; but it cannot naturally be separated generically 

 from B^tljjMoea tinctoria, of which it has the structure, though 

 differing abundantly in specific character. Notwithstanding the 

 thickness of the cortical layer, the " transverse stria," characte- 

 ristic of a Bytipldcea, are plainly marked on all the younger por- 

 tions at least. The distinction, however, between the filiform 

 species of MytipUcea and Bhodomela is not very well marked, 

 and depends more on the comparative size of the axile tubes and 

 comparative thinness or translucency of the cortical layer than on 

 any definable structural difference. 



Fi"". 1. Rytiphlcea elata, branch of a large frond, — the natural size. 2. Sec- 

 tion of a branch. 3. 'YvSi 0^ stichidia. 4. A ce?'amidium : — all mafjmjied. 



