No. 61 NEW MELOBESIEAE. 21 



it approaches Lithoph. verrucosum, the latter hitherto only known 

 from Australia. G. Notarisii is an extremely varying species, and the 

 limits of it appear to be difficult to draw judging from the mate- 

 rial at my disposal. I venture however to adopt the present plant 

 as a new species especially on account of the structure which 

 certainly rather approaches forms of G. Notarisii, but on the 

 other hand it cannot be referred to this. 



The species has been collected at St. Croix, West India, by 

 Mr. F. Borges en. Here it grows together with a somewhat 

 stunted form of G. mamillare. A. yong specimen on a Coral 

 from Barbados (Prof. G. Lagerheim) seems to belong to the 

 same species. 



G. Udoteae Fosl. mscr. 



Thallus crustlike, of indefinite shape and extent, 150 — 200 p- 

 thick, with almost smooth surface. Conceptacles (of sporangia?) 

 conical, 800 [i in diameter at the base. 



The species forms light rosy, suborbicular, at length confluent 

 crusts of indefinite shape and extent on Udotea, 150 — 200 p thick. 

 New crusts are occasionally formed upon the primary, or when 

 trumbling the one crust sometimes stretches itself over the other 

 but loosely clinging to the subjacent. The surface is smooth or 

 slightly rugged, in the latter case mainly caused by covering up 

 small extraneous objects. 



A section of the crust shows a proportionally vigorous hypo- 

 thallic layer occupying almost the lower half of the crust. It is 

 composed of rather irregular cells which are frequently elongated 

 and up to twice as long as broad, or 15 — 30 /j- long and up to 

 15 jj. broad. The lower rows are almost horizontally stretched 

 over the substratum. The perithallic cells are rounded, 7 — 15 //. 

 in diameter, sometimes however square or a little vertically elon- 

 gated. Heterocysts are rather numeraus and large, about 36 /x long. 



I have seen but a couple of not well developed conceptacles 

 onspecimens tåken in January — March, and I am not sure whether 

 they are those of sporangia or perhaps cystocarps. They are 



