THE DIGESTIVE ORGANS OF THE ALCYONARIA. 3845 
gleaned, which have an important bearing on the question of 
the occurrence of an inter-cellular digestion in Aleyonium: 
1. Large food bodies are rapidly broken up into small 
particles, and in some cases apparently acted upon by some 
digestive ferment in the ccelentera of the zooids before they 
are ingested by the ventral mesenterial filaments. 
2. The mesenterial filaments of hungry zooids are crowded 
with gland cells containing numerous granules. 
3. hese gland cells also occur in the stomodeeum and 
mouth dise of hungry zooids. 
4. The mesenterial filaments of zooids immediately after 
feeding contain very few granular gland cells in which the 
granules are numerous, many cells contain very few granules, 
and several gland cells are empty. 
5. The stomodzum and mouth disc of zooids immediately 
after feeding are usually devoid of granular gland cells. 
The only inference to be drawn from a consideration of 
these facts is that the gland cells of recently-fed zooids have 
poured on to the food, during its passage through the 
stomodeum and envelopment by the filaments, a digestive 
secretion, which has brought about its disintegration and 
partial solution before its ingestion by the mesenterial fila- 
ments. ‘Therefore, we have evidence inthe Alcyonaria, as in 
the Madreporaria, of an inter-cellular digestion by the secre- 
tion of a digestive fluid into the celentera of the zooids, as 
well as an intra-cellular digestion which occurs throughout 
the Coelenterates. 
I have already drawn attention to the fact that food 
material is seldom observed in the ccelentera of the zooids in 
Alcyonaria (p. 331). This is especially the case with regard 
to tropical forms, and has been commented upon by several 
authors (p. 347). 
Histologically, the stomodzum and ventral mesenterial 
filaments differ to a greater or less degree from those of the 
British Aleyonium digitatum. Several tropical species, 
Sarcophytum glaucum, Sclerophytum capitale, pal- 
matum, densum, etc., give rise to a copious mucous secre- 
