THE ROLE OF MUCUS IN CORALS. 607 
reaction), a response which will be discussed in another 
contribution. . 
The experiments described suffice to show that the feeding 
reactions of the colonial coral Favia closely resemble those 
of the single polyp of Fungia. ‘The differences, such as 
the more complicated character of the superficial currents 
and the continuity of the mucous streams, are such as are 
dependent upon the colonial condition. As in Fungia, 
there was no evidence that the external surface of Favia is 
ciliated. 
Throughout the experiments there was no indication that 
the food during ingestion was actually grasped by the lips or 
that its indrawal was directly assisted by peristaltic move- 
ments of the stomodzal walls. When the particles were 
small they were simply carried along in the inhalent stream, 
whether of water or mucus, without coming into direct 
contact with the lips or stomodeal walls, or without any 
movements of these. When the fragments were large the 
oral aperture became wider and wider to admit them, and 
then closed after their admission. Even here their motion 
downwards was of a gliding character, though there can be 
no doubt that when, on account of their size, the fragments 
come into direct contact with the stomodeal walls they will 
bring about reactions of the organ. Torrey! considered that 
the peristaltic movements of the cesophagus in Sagartia 
davisi may assist the cilia, but found no evidence that they 
take more than a very subordinate part in the swallowing 
or disgorgement. In the case of Hydra, Wagner” found 
that as soon as food touches the hypostome the mouth begins 
to open and its edges fasten to the meat. ‘he actual process 
of swallowing here depends entirely on the activity of the 
tissue of the hypostome and body. Wagner regards it as 
difficult to see how cilia could have enough strength to play 
1 «On the Habits and Reactions of Sagartia davisi,” ‘ Biol. Bull.,’ 
vol. vi, 1904, p. 215. 
2 “On some Movements and Reactions of Hydra,” ‘Quart. Journ. Mier. 
Sci.,’ vol. 48, 1905, p. 609. 
