are wide, but sharp, the branches and ramuli patent or divaricate. The 

 apices are not remarkably recurved, and only show such a tendency in the 

 cystocarpic specimens. The tips of those bearing tetraspores are quite 

 straight, spreading, but not generally recurved, oblong or ovate -oblong. 

 The cystocarps are near the bluntly acuminate end of the branch ; the 

 spores are obovate, on longish pedicels. Tetraspores zonate, very nume- 

 rous, lodged in the cortical layer of the pod-like extremities. The colour is 

 a deep, full red, becoming darker and duller in drying. The substance is 

 rigidly cartilaginous, somewhat horny when dry, and the frond very im- 

 perfectly adheres to paper in drying. 



At Plate LXXIV. is represented another species of Dicranema 

 closely allied to the present, but of much smaller size, and with 

 the tips much more strongly hooked. Notwithstanding their 

 near affinity, I am disposed to regard these Algae as sufficiently 

 distinct, nor have I yet met with any puzzlingly intermediate 

 forms between them. Both grow commonly on the hard stems 

 of the Cymodocea, but while the present is found along the 

 whole western and southern coasts, the former is very local, and 

 by me only met with at Cape Riche. 



The genus Dicranema^ placed by Agardh among SphcBrococ- 

 coidea, appears to me to range better with the Gelidlacca, both 

 because the placentae are parietal, and derived from the medul- 

 lary filaments, and because the nucleus is composed of pedicel- 

 late, single spores, not forming moniliform series. To me the 

 cystocarp appears like that of a Hypnea, condensed ; differing in 

 the more columnar form of the placenta, and, consequently, the 

 more closely-placed spores. The substance of the frond, too, is 

 of the rigid, half-horny character of the Gelidia, and the dicho- 

 tomous ramification, though unusual in Gelidiacets, occurs in a 

 species of Gelidium itself. 



Fig. 1. Dicranema Grevillei, — the natural size. 2. Tips with imbedded 

 conceptacles. 3. Section of a conceptacle. 4. Spores from the same. 

 5. Tips with tetraspores in the dilated extremities. 6. Cross section, 

 showing the tetraspores in situ. 1. Tetraspores removed : — the latter 

 figures variously inagnified. 



K^ 



