larger thaa broad, and zonate. The colour is a dark brownish-red, becoming 

 much darker and even blackish in drying. The substance is tough, leathery 

 when dry, and the plant does not adhere to paper in drying. 



If I am correct in referring the plant here figured to the 

 Acrotylus australis, J. Ag., of which I have seen no authentic 

 specimens, and the cystocarpic fruit of which was not known 

 to Prof. Agardh when he founded his genus Acrotylus, then 

 the genus must be placed in Gelidiaceoi (tribe ChcetangiecB), 

 instead of among the CryptojiemiacecB, where Agardh puts it ; 

 and also, the two species of the subgenus Prismatoma must be 

 separated. This separation will reduce Acrotyhs to the single 

 species now described ; and this has so much of the external 

 aspect of a Chcetangmm, of the section Nothoyenia, that the pro- 

 priety of keeping it separate may be questioned. The characters 

 by which Acrotylm differs from Chcetangium are found in the 

 more or less developed " intermediate stratum " of roundish an- 

 gular cells {yonidia), and in the tetrasporic sori of the present 

 genus. In Chcstanyium the tetraspores are dispersed, and the 

 frond composed wholly of filaments. 



My first specimens of Acrotylus australis were given me by 

 Dr. Curdie, of Geelong, and not then recognizing them as the 

 plant previously described by Agardh, I named them " Curdiea '* 

 in his collection. I have since selected another Curdiea (Plate 

 XXXIX.) which I hope may prove a more permanent memento. 



Fig. 1. AcKOTYLUS AUSTRALIS, — the natural size. 2. Portion of a branch, 

 with conceptacles, — slightly magnified. 3. Section through the frond and a 

 conceptacle. 4. Section through a sorus ; and 5, a telraspore: — variously 

 magnified. 



