No. 6] NEW MELOBESIEAE. 9 



in a steril stage considered to be a separate species. In f. sub- 

 lævis the crust is thin and smooth or almost so, firmly adhering 

 to the substratum, the peripherical portion concentric zonate, with 

 more or less entire margin and a whitish brim. More crusts 

 founded on the same substratum at length become fully confluent, 

 now and then especially towards the margin sometimes showing 

 small elevated edges where two crusts trumble. The conceptacles 

 of sporangia are frequently less prominent than in the typical form, 

 more flattened and often larger, in this respect on the one side 

 approaching L. Sondert and on the other hand L. læve. In f. 

 squamulosa the scaly and more or less irregular thallus-leaflets are 

 rather loosely formed over each other, at length forming an irre- 

 gular crust-complex up to about 7 mm. thick and almost loosening 

 itself from the substratum. The conceptacles of sporangia in this 

 form resemble those in f. typica, in which they are frequently 

 hemispheric, or when the roof being on the point of dissolving 

 somewhat flattened or depressed in the central parts. The latter 

 and well-known form shows transitions partly to f. sublævis partly 

 to f. squamulosa which such in fact are nearly connected, but on 

 the other hand must be considered as tolerably well marked forms. 



The form australis shows variation in another extreme direc- 

 tion than the curious f. squamulosa, or to be considered as a 

 further developed f. sublævis, with frequently thicker crust than 

 the latter, and the conceptacles even less prominent.- The hypo- 

 thallic, more or less horizontal cell-rows are less in number than 

 in the said form, the cells a little larger and frequently with thicker 

 walls, sending lorth a rather vigorous perithallic layer the cells of 

 which resemble those in the typical form, however not so fre- 

 quently a little vertically elongated, seldom up to l 1 /* times longer 

 than broad, and occasionally with the longest diameter in hori- 

 zontal direction as in f. typica. 



The form australis has been found in Half-moon Bay, Port 

 Phillip Bay, Victoria, and a solitary specimen agreeing with f. sub- 

 lævis has been gathered at Port Phillip Inlet, east of Port Phillip 

 Bay, both by Mr. J. Gabriel. 



