55 



Melobesia Lamour. (Fosl. emend.). 



Subgen. Eumelobesia Fosl. 



i. Melobesia subtilissima Fosl. mscr. 



Thallus forming delicate, monostromatic patches of indefinite shape. Conceptacles /of 

 sporangia subhemispherical, about 60 u.. in diameter. 



Stat. 169. Off Atjatuning, West-coast of New Guinea. Reef. 



This species forms delicate patches on Corallina pilifera. The patches are partly very 

 small, partly somewhat expanding over the branches of the host, but rarely covering parts of 

 the joints of the latter. The plant is dimcult to detect, as it shows the same light colour as 

 the host in a dried stage. The peripherical portions of young specimens are sometimes not 

 confluent, but short subdichotomous rows are formeel, which here and there are anastomosing 

 as in M. farinosa Lamour. f. callithamnioides (Fkbg.) Fosl. mscr. and M. zonalis (Crn.) Fosl. 

 The crust is monostromatic except in the neighbourhood of the conceptacles, and it is destitute 

 of cortical cells. I have at any rate been unable to detect such ones in the material in hand. 

 In a surface view the cells are partly squarish, 4 — 6 u.. in diameter, partly and especially 

 towards the peripheral portions rectangular and 7 — 9 u.. long. In a vertical section they are 

 also squarish or slightly vertically elongated. 



The conceptacles of sporangia appear scattered, and they are on the whole rather scarce. 

 They are subhemispherical and about 60 u.. in diameter, when seen from the surface, with a 

 single orifice. The sporangia are four-parted, about 25 y.. long and 12 u.. broad. The plant 

 bears ripe ones in the month of August. 



The species in question comes nearest to Melobesia rugulosa Setch. et Fosl. from the 

 coast of California. It is, however, distinguished by essential characteristics, particularly smaller 

 cells and smaller conceptacles. 



Occurrence: The plant is only known from the station above quoted, where it seems 

 to occur rather sparingly on the host plant mentioned. 



2. Melobesia farinosa Lamour. 



Hist. Polyp. p. 315; Rosan. Melob. p. 69. 



Stat. 40. Pulu Kawassang, Paternoster Islands. On eelgrass '). 



Stat. 43. Pulu Sarassa, Postillon Islands. On eelgrass. 



Stat. 45. 7 24' S., n8°i5'.2E. On Turbinaria decurrens. Drifting. 



Stat. 53. Bay of Nangamessi, Sumba. On eelgrass. 



Stat. 66. Saleyer. On eelgrass. 



Stat. 99. North-Ubian. On eelgrass. 



Stat. 131. Beo, Karakelang Islands. On Valonia ventricosa. 



1) By eelgrass I mean phanerogamous plants with long, linear leaves. These leaves may belong either to Cymodocea, Poscidonia 

 or Enalis^ three plauts of frequent occurrence in the investigated area. Those specimens covered with Melobesia were sterile, and they 

 are therefore hardly to be alleged. 



