THE DIGESTIVE ORGANS OF THE ALCYONARIA. 3843 
presence of gland cells in the ventral mesenterial filaments of 
Paraleyonium was first observed by Wilson, 1884, who 
states that they are similar to those observed by the Hertwigs 
in the Actinians. He also describes the occurrence of 
ingested foreign bodies in the filaments. 
Hickson (1895, p. 367) described two kinds of gland cells 
in the ventral filaments of Alcyonium digitatum, one 
kind being large, unciliated, and deeply staining with hema- 
toxylin, the other consisting of elongated columnar cells 
filled with numerous minute granules. He further states 
(1901, p. 12) that the function of the ventral filaments is to 
secrete a digestive juice upon particles of food which have 
passed through the stomodzum. 
J. Stanley Gardiner (1900 and 1902) describes the occur- 
rence of granular and mucous cells in the mesenterial fila- 
ments of the Madreporaria, and in his description of 
Flabellum says :—“ Every stage of ingestion and protrusion 
of foreign matter could be seen in the swollen-out endodermal 
bases of the mesenterial filaments, but elsewhere was not 
observed. The storing up of round, fat globules, not only in 
the endoderm at the bases of the mesenterial filaments, but 
anywhere in the endoderm, indicates that there must be a 
true digestion—due to the secretion of the gland cells of the 
mesenterial filaments—and absorption over the whole endo- 
derm, as well as ingestion at the bases of the filaments. No 
absorption would, however, seem to occur in the mesenterial 
filaments, the concentration of fat, etc.,in the endoderm at 
their bases being correlated with this.” 
The Zoantharia are well known to be widely separated 
genetically from the Alcyonaria. Nevertheless, the record of 
the secretion of a digestive juice is of great importance, for 
in a recent publication Mesnil (1902) states that digestion in 
the Actinians is entirely intra-cellular, and denies the 
occurrence of an inter-cellular digestion in the group. 
This statement is based on the result of a number of experi- 
ments of a chemico-biological character. 
On comparing sections of the ventral filaments of recently- 
VOL. 49, PART 2.—NEW SERIES. 24 
