6 M. FOSLIE. [1908 
up to 120 p. The alga is, as yet, known only from Mada- 
gascar (Jadin). 
Melobesia (Pliostroma) explamata Fosl. msecr. 
Lithophyllum (Carpolithon) explanatum Fosl. Alg. Not. II (1905) 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) p 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 more. The alga is known 
only from New Zealand, where it occurs in Island Bay, near 
Wellington (Setchell!). 
Melobesia (Pliostroma) Sargassi Fosl. mser. 
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 (Yendo)). 
Melobesia (Pliostroma) Chamædoris Fosl. et Howe mser. 
Lithophyllum (Carpolithon) Chamædoris Fosl. et Howe New Amer. Corall. Alg, 
(1906) p. 134, på. 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) p 
long and 7 (6)—11 (13) p broad with 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 
