quite sessile or on a very short, scarcely obvious stipes, more or less densely 

 imbricated throughout with tri-quadrifarious ramenta. Bamenta 2-3 lines 

 long-, at first nearly cylindrical, but becoming more or less distinctly linear- 

 clavate, thickening at the very obtuse extremity. The colour is a peculiarly 

 vivid and pleasant green, becoming darker and more olivaceous in the her- 

 barium. The substance is rather soft and succulent, and in drying the 

 frond adheres, though not strongly, to paper. Var. /3 differs from the com- 

 mon form chiefly in being depauperated, with shorter and more slender 

 stems, and fewer and more distantly inserted ramenta. 



An authentic specimen, communicated by Dr. Sonder, now 

 enables me with confidence to refer the plant here figured to 

 that author's C. cylindracea. I had previously associated it 

 with C. Icetevirens, Mont., and on now comparing my figure 

 with that published by Montagne, there is so near an agreement 

 that, allowing for differences of habitat, and of artists, I am still 

 disposed to think the plants the same. I have not however 

 seen any authentic specimen of Dr. Montagne's species. He 

 represents the ramenta as more densely imbricated, and rather 

 longer, and perhaps a shade more club-shaped than I find them. 

 But my specimens differ as much in these respects from each 

 other as do Montagne's and my figures. This plant is exces- 

 sively common on all the reefs at Rottnest Island, growing in 

 shallow, exposed tide-pools, as well as in sheltered spots below 

 low-water mark, and it varies much in luxuriance according to 

 the locality. 



As a species it is obviously nearly related to the protean C. 

 clavifera, but appears to be sufficiently distinct. 



Fig. 1. Caulerpa cylindracea ; and fig. 2, the var. (3, — both of the natural 

 size. 3 and 4. Ramenta, of different ages, — moderately magnified. 



