22 M FOSLIE. [1900 



conical, about 800 p in diameter at the base and of about the 

 same height 



This species stands near to G. Notarisii, but is distinguished 

 both in habit and structure. 



It is hitherto only known from West India, on TJdotea fiabel- 

 lata at St. Croix, Little Princess, collected by Mr. F. Borgesen. 



Melobesia Lamour. emend. 

 Subgen. Eumelobesia Fosl. 



M. bermudensis Fosl. mscr. 



Thallus forming delicate patches of indefinite shape and extent 

 on stones, about 30 \i thick, superposing at length up to 150 ;i 

 thick. Conceptacles of sporangia superficial, hemispheric-conical, 

 150 — 180 p. in diameter. Sporangia four-parted, 55 y- long by 30 ji. 



The species forms small or larger, more or less irregular patches 

 on a kind of loose limestone, at length confluent or nearly so, of 

 indefinite shape and extent, with entire or crenulate margin. The 

 crust is not quite smooth which however apparently depends on 

 the uneveness of the substratum. It is dull, and the colour is in 

 a dried state a greyish-white, only a little differing from that of 

 the substratum, however nere and there with a feeble rosy shade. 



On a vertical section of the crust the basal cells are shown 

 to be square or most frequently vertically elongated, 10—18 /* 

 high by 10—12//, with rather thick walls and very small cortical 

 cells. A solitary layer of a crust frequently has a thickness of 

 about 30 ;j; but very often the one crust stretches itself over the 

 other, and up to 5 or 6 superposing crusts are sometimes to be 

 found by a thickness of up to about 150 /*, each of them partly 

 loosely partly closely clinging to the subjacent. 



The conceptacles of sporangia frequently are densely crowded 

 especially in somevvhat extended crust-complexes, superficial and 

 hemispheric-conical, 150—180 ;->- in diameter at the base. The 

 sporangia are four-parted, about 55 \i long by 30 fi. 



The species stands on the one side near to Melobesia caspia 



