M. FOSLIE. [1908 



up to 120 /Jt. The alga is, as yet, knovvn only from Mada- 

 gascar (Jadin). 



Melohesia (Pliostroma) explanata Fosl. mscr. 



Lithophj'UuiTi (Carpolithon) explanatum P'osl. Alg. Not. Il (IW') p. 25. 



Only a small marginal part is monostromatic. In this part of 

 the thallus the cells, as seen from the surface, are elongated in 

 the direction of the radius. They are 9 (7)— 18 (22) jj. long and 

 6 (5)— 9 (11) p. broad, and the cortical cells are oblong or semi- 

 circular. In the other parts of the thallus are developed up to 

 seven layers of cells, perhaps in part moi^e. The alga is known 

 only from New Zealand, where it occurs in Island Bay, near 

 Wellington (Se te heil!). 



Melohesia (Pliostroma) Sargassi Fosl. mscr. 



Lithophyllum (Carpolithon) .Sargassi Fosl. Alg. Not. II (1906), p. 26. 



This species encompasses, wholly or in part, the airbladders 

 of Sargassum, peculiarly S. serratifolium. The monostromatic 

 part of the thallus is frequently of very little extent. Here the cells, 

 as seen from the surface, are elongated in the direction of the 

 radius, 11 — 18 (20) p. long and 6—9 p broad. The cortical cells 

 are oblong, semicircular or sometimes roundish. As a general rule, 

 several small thalli settle on one and the same airbladder and 

 finally grow confluent. The pluristromatic part is composed of 

 up to about 10 layers of cells and is up to 90 p thick. The 

 species is known only from Misaki, Japan (Yen do!). 



Melohesia (Pliostroma) Chamædoris Fosl. et Howe mscr. 



Lithophyllum (Carpolithon) Chamædoris Fosl. et Howe New Arner. Corall. .'\lg. 

 (1906) p. 134, pi. 90, fig. 1. 



Also in this species the monostromatic part is of little extent. 

 In this part the cells, as seen from the surface, are 11 — 22(25)/^ 

 long and 7 (6) — 11 (13) p broad wilh oblong cortical cells. The 

 alga often completely encircles larger or smaller parts of the stalk 

 of the host plant, and in this case a transverse section will only 

 show a crust composed of several layers. It forms up to twelve 



