lesser divisions. The form and ramification and size are much varied ; the 

 margin in some specimens is ([uite flat and entire, in others sljirhtly toothed, 

 and in others deeply cut, serrated, and fimbriato-hicerate, either flat, undu- 

 lated, or curled. The apices of all the branches and of their lesser divisions 

 are very acute; those of the smaller ones much acuminated. No fruit seen 

 on the Australian specimens. Colour a bright pinky-red, soon discharged, 

 with decomposition, in fresh-water. Substance very softly gelatinous, some- 

 times distended. In drying this plant adheres most closely to paper. 



Halymenia Floresia, a widely-distributed species, is very va- 

 riable in ramification on almost all the shores on which it is 

 found; specimens from the same locality differing as much one 

 from anotlier as those that may be brought from the ends of the 

 earth. In all its states, however, it is recognized from the near- 

 est species by the very sharp or attenuated, marginal or terminal 

 segments and lobes. Some of Mr. Clifton's specimens are of 

 great size and breadth, and amply furnished with marginal fringe, 

 quite like what I collected at Port Phillip ; while some of my 

 Premantle specimens, that grew side by side with Mr. Clifton's, 

 are narrow and bare, like a common form found at Venice and 

 Trieste. 



On comparing Australian individuals with those from Europe, 

 I find the frond to be thicker and the cellular substance more 

 dense, but not so decidedly the one or the other as to afford a 

 valid distinction. Externally there is no difference to be noted. 



Fig. 1. Halymenia Floresia, — the natural size. 2. Section of the frond, — 

 magnified. 



