parent gelatine, varying in consistence in different specimens, being some- 

 times firm, sometimes lax and slimy : it is developed in the large cells of the 

 centre, vehich soon perish, and have not yet been carefully examined in fresh 

 and young specimens. In drying the gelatine disappears, the membranous 

 frond adheres most closely to paper, and the cells very imperfectly expand 

 on re-moistening. The conceptacular fruit consists offavellidia, immersed in 

 the frond, below the intermediate layer ; they are plentifully scattered over 

 the surface of the bags. Tetraspores have not yet been seen. The colour 

 varies from rose-red to livid-purple, and the dark-coloured specimens are 

 generally (but not always) more rigid than the brighter-coloured. 



In distributing ray Alg. Exsic. Austr., I mistook the present 

 plant for a Halosaccion, a genus of the North Pacific Ocean, 

 having a very similar external habit, but (as I now know) a dif- 

 ferent structure, and probably (?) dissimilar fruit. The ba^s in 

 Halosaccion are filled with air or with sea- water, and are of a rigid 

 substance, and densely cellular structure; in our new genus 

 Gloiosaccion^ they are normally filled with jelly, and the structure 

 is more lax, and substance greatly softer. I venture to refer to 

 the F. allantoideSy R. Br. MS., thus noticed by Turner in his 

 account of F. saccatus {Halosaccion) : — " A third Fucus, which 

 seems in a great measure allied to both these, has been sent to 

 me by Mr. Brown, from New Holland. Its interior is filled 

 with gelatine, its membranous coat partakes of the same gelati- 

 nous nature, and its shape is remarkably pyriform," — all which 

 characters answer to the species now figured. Our two varieties 

 differ chiefly in colour ; and numerous specimens, from various 

 stations, show the passage of one form into the other. I once 

 found a specimen forking twice, and thus resembling Scinaia 

 furcellata. 



Fig. 1. Fronds of Gloiosaccion Brownu, — the natural size. 2. Section of 

 membrane, to show cellular structure. 3. A similar section, cutting through 

 a favellidium : — the latter figures highly magnified. 



