below their middle, and about a line in length. The apices of the prongs 

 of the fork are emarginate, each lobe simply (not doubly) mucronulate. 

 Generally the frond is but once pinnate ; but in luxuriant specimens the 

 racliis throws out secondary rachides, which are in turn pinnated, and a bi- 

 pinnate or even dendroid frond is formed. The colour is a peculiarly bright 

 grass-green, inclining to yellowish in age. The substance is soft and flaccid 

 in thepinnated portion of the frond, which adheres closely to paper; but 

 rigid and rough in the stipes and surculi, which do not adhere to paper. 



By comparing the Plate now given with Plate II. {C. Muelleri), 

 the resemblances and differences between these closely allied 

 species may be seen. Externally the present differs from the 

 former in its bright-green or yellowish colour, in the more lan- 

 ceolate general outline, and in the more laxly set and patent or 

 squarrose ramenta. The microscope reveals another and more 

 essential character ; the ramenta in C. hypnoides being forked 

 near the middle; and in C. Muelleri at the very base. The 

 present is much the commonest species ; extending along the 

 whole west and south coasts of Australia, and to Tasmania and 

 New Zealand. It bears a remarkably close resemblance to a 

 Swiss fossil, figured by Brongniart, under the name " Fucoides 

 hypnoides" (Brongn. Hist. t. 9 bis, t. 1-2). 



Fig. 1. Caulerpa hypnoides, — the natural size. 2 One of the forked ramenta. 

 3. Apex of one of the prongs. 4. One of the dichotomous scales from the 

 surculus : — the latter figures variously magnified. 



