346 EDITH M. PRATT, 
tion. In these forms mucous gland cells are extremely 
numerous in the stomodeum (figs. 5 and 6). 
In tropical forms the mesenterial filaments are frequently 
small compared with those of colonies inhabiting temperate 
waters. This is particularly noteworthy in the tropical 
specimens of Alcyonium pachyclados. In specimens 
from the Cape which have been attributed to this species the 
mesenterial filaments are fairly well developed, but in colonies 
from the Maldive Islands they are either extremely small or 
entirely absent. The enormous size of the filaments in 
Sarcophytum I have shown to be entirely due to the 
thickening of the mesogloea of the mesentery near the free 
edge (fig. 12), and cannot in any sense be regarded as an 
increase of digestive surface. In many cases of this genus 
the mesenterial filaments are small compared with those of 
the British genus (figs. 10 and 12), and contain few granular 
gland cells.! 
The filaments are apparently larger in Sarcophytum 
glaucum than in any other species, but it is to be regretted 
that several specimens are not sufficiently well preserved for 
the study of the histology of the filaments; when gland cells 
are present they are similar to those of Aleyonium (fig. 10), 
and doubtless fulfil the same function. 
The mesenterial filaments of Sarcophytum latum closely 
resemble those of Lobophytum, but as this species resem- 
bles Lobophytum in several other respects (Pratt, 1903) 
it should henceforth be included in this genus. 
These filaments in Lobophytum are more like those of 
the British form than any other tropical genus in the collec- 
tion. They are, however, smaller than in our species of 
Alcyonium, and it is interesting to note that zoochlorelle 
are by no means numerous. 
The ventral filaments of Sclerophytum vary considerably 
in different species (cf. Table, Pratt, 1903, p.531). They are 
1 The scarcity of granular gland cells in the mesenterial filament (fig. 13) is 
not to be confused with the empty condition of these cells in Aleyonium 
after feeding (fig. 11). 
