formed of very densely compacted and agglutinated longitudinal filaments, 

 exactly as in Chordaria, and the peripheric ramelli form a very thin, velvety 

 pile on the surface, and are also of the character of those of a Chordaria. 

 The spores are obovoid, and abundantly produced. The substance is softly 

 membranous, and somewhat gelatinous, and the plant adheres closely to 

 paper in drying. The colour is a dark brown. 



Except in having a hollow and tubular instead of a solid axis, 

 the plant here figured does not differ from Chordaria, and pro- 

 bably it would be better to retain it as a species of that genus. 

 Tn different localities it varies much both in size, diameter, and 

 ramification ; and I had at first sorted and distributed the spe- 

 cimens under three supposed species. On more closely examin- 

 ing with the microscope, I find the structure so similar in all, 

 and the ramification and size so variable, when traced through a 

 long suite of specimens, that I am forced to unite n. 95, 96, 

 97, of my Alg. Exsic. under the present species, It ranges 

 over a considerable length of coast. The specimens from George- 

 town, Tasmania, are very much larger and more robust than our 

 figure, taken from a Port Phillip specimen. The deep estuary 

 of the Tamar seems peculiarly favourable to the growth of all 

 Algae, as is well known to Tasmanian collectors. 



Fig. 1. Cladosiphon Chordaria, — the natural size. 2. Longitudinal seini- 

 section of a branch. 3. Transverse section of the same. 4. Small portion 

 of the periphery, with spores in situ. 5. A peripheric filament and spore 

 at its base : — the latter figures variously magnified. 



