the spores in some other species (fig. 4, 5); but no spores here accompany 

 them. The substance of the frond is rather thick, and somewhat opaque ; a 

 section shows a double row of large, empty, quadrate medial cells, and a 

 single row, at each side, of coloured cellules. The colour is a dark-brown, 

 becoming almost black in drying, in which state the plant does not adhere 

 to paper. 



This species is readily known from all the forms of D. dicJio- 

 toma by its much thicker, more rigid, and darker-coloured fronds, 

 and by its cellular characters. It appears to be a true Bictyota, 

 not a Stcechospermum, as Professor Agardh, judging from de- 

 scription, supposes. I have not seen the normal fruit. The 

 scattered spores (?) described above are probably antheridia. It 

 is ^to be hoped that Mr. Clifton may succeed in finding fruit. 

 The species is commonly thrown up in winter along the shores 

 of Western Australia. I have only seen a single specimen from 

 Flinders' Island ; and it has not yet been found in any other 

 part of Bass's Straits, or further east than Cape Riche. 



Our figure is faulty in one respect ; the apices of the laciniae 

 ought to be very minutely, but sharply, indented. They are 

 commonly so, but not constantly, as it so happened that a per- 

 fectly entire apex was selected for figuring. 



Fig. 1. DicTYOTA FASTIGIATA, — the natural size. 2. Apex of a lobe. 3. 

 Small portion of the surface, with a cluster of paranemata, seen vertically. 

 4. The cluster, seen laterally. 5. Some of the paranemata removed. 6. 

 Small portion of surface, with a solitary spore? 7. Section through the 

 membrane : — the latter figures variously magnified. 



