No. 11] — PLIOSTROMA A NEW SUBGENUS OF MELOBESIA/ G 
layers of cells and attains a thickness of up to 150 p, though 
usually less. Cp. 1. c. The conceptacles of sporangia here men- 
tonedirepresent in fact as I opservedf in Ag No Vi påle 
conceptacles of cystocarps. The species occurs at the Bahamas 
(Howe) and at St. Croix in the West Indies (Børgesen)). 
The following species are still to be kept under Carpolithon, 
subgenus of Lithophyllum, with a single layer of basal hypothallic 
cells and several layers of perithallic cells: 
Lithophyllum tasmanicum Fosl. 
å paradoxum Fosl. 
Jugatum Fosl. 
” 
