334 Dr. W. H. Harvey on new genera and species of AlgcB. 



ptoneme(B. I have now collected numerous fruiting specimens, 

 and find that the structure of the cystocarp is identical with that 

 of Chcetangiumy near which genus Acrotylus must now be placed. 

 It is in fact very closely related to the section Nothogenia. 



3. GuLSONiA, Harv. 



Frons gelatinoso-membranacea, teres, nodoso-annulata, de- 

 composite ramosa, ex tubo centraii crasso articulate monosi- 

 phonio filis anastomosantibus longitudinalibus laxe circumdato, 

 et filis horizontalibus excurrentibus dichotomis fastigiatis muco 

 hyalino firmiori inclusis constituta. Fructus 



Gulsonia annulata, Harv. 



Cast ashore, Phillip Island, Western Port. Rare. 



Fronds densely tufted, 6 to 8 inches long, decompoundly much 

 branched, the branches and their divisions and ramuli irregularly 

 scattered, all tapering to the base and apex, and all annularly 

 constricted at short intervals; the nodes swollen and deeply 

 coloured, the internodes pale, like very narrow transverse rings. 

 A cross section shows a very large central tube, surrounded by a 

 narrow stratum of longitudinal filaments, from which radiate 

 towards the circumference, dichotomous, callithamnoid, fastigiate 

 filaments, whose branches are separated by pellucid jelly of firm 

 consistence, a layer of which also forms a pellucid envelope of 

 the branch. A longitudinal section shows that the central tube 

 is septate, the septa at intervals of 6 or 8 diameters apart ; and 

 that the longitudinal filaments anastomose into a laxly netted 

 filamentous sheath, enclosing the central tube. The filaments 

 of the periphery are thrown ofi" irregularly from the outer part 

 of this sheath. Colour a fine pinky-red, staining the paper on 

 which the plant may be dried. Substance very soft. 



This beautiful plant, of which the fruit is at present unknown 

 to me, seems to be the type of a new genus of CryptonemiacecBy 

 which I inscribe in honour of Mrs. Gulson of Exmouth, whose 

 explorations of the shells and Algse of the Devonshire coast are 

 well known to and appreciated by British naturahsts. Prom its 

 structure I am disposed to place Gulsonia near Catenella or 

 Gattya, from both which it difi'ers sufficiently in habit, sub- 

 stance and structure to forbid its union under either. It may 

 also be compared to Gloiopeltis and Endocladia, but differs 

 essentially from these in several particulars. In external habit 

 it may be compared to a gigantic Crouaniaj or to a Lomentaria 

 or a Champia with very short joints and of a very soft substance. 

 In size, colour and substance it something resembles Champia 

 affinis when fresh, but more rapidly decomposes. 



