drying. Substance rather rigid. The plant imperfectly adheres to paper 

 in drying. 



When I named and distributed this little plant as B. simpli- 

 ciuscula, I was not aware that my excellent friend Dr. Mueller 

 had already communicated it to Dr. Sonder, by whom it is well 

 described in the Linnsea, under the name now adopted. Dr. 

 Mueller's and my specimens were probably collected from the 

 same rocks, one of the ledges uncovered at low tides, on the 

 strand, near the " Royal Hotel," at the Australian " Brighton." 

 Those from different localities in Tasmania agree in most cha- 

 racters ; but Mr. Stuart's specimens grow on the stems of C'j/mo- 

 docea antarctica, and slightly differ. 



The structure of the stem may be compared to that of Polg- 

 siphonia Hookeri, but the cells are more closely pressed, smaller, 

 the articulated axis less obvious, and there is no tendency to 

 external articulation even in the smallest and youngest ramuli. 

 The surface-cells in all parts of the opaque frond are minute and 

 irregularly polygonal. The ramuli in capsuliferous specimens 

 are always simple or nearly so ; in those that bear tetraspores 

 they are frequently multipartite and corymbose. 



Fig 1. Rhodomela periclados, — the natural size. 2. Part of a branch, with 

 capsuliferous ramuli. 3. Apex of a ramulus, and ceramidium. 4. Tuft 

 of spores. 5. Multifid ramulus, bearing tetraspores. 6. A tetraspore. 

 7. Cross section of the frond : — the latter figures more or less magnified. 



