THE ROLE OF MUCUS IN CORALS. 591 
The Role of Mucus in Corals. 
By 
J. E. Duerden, Ph.D., A.R.C.Sc.(Lond.)., 
Professor of Zoology at the Rhodes University College, Graliamstown, 
Cape Colony. 
WITHIN recent years much advance has been made in our 
knowledge of the physiology of actinian polyps by investiga- 
tors such as Nagel, Loeb, Parker, Carlgren, and Torrey. 
Comparatively little, however, is yet known of the living 
activities of the closely-related madreporarian polyps. As 
regards actinians several contributions have appeared giving 
the results of observations and experiments upon ciliary 
activity and its significance in the feeding of the polyps, and 
it was while carrying out similar studies upon the madre- 
porarians that it became evident that mucus likewise holds a 
place of much importance in the ingestion of food. ‘The pre- 
sent account deals in the main with only this factor in the 
physiological processes of corals, namely the part played by 
mucus. ‘The observations and experiments were carried out 
inthe Hawaiian Islands, mostly upon the living mushroom 
coral Fungia, and the compound astraeid Favia.’ The work 
1 Several species of Fungia have been described from the Hawaiian 
Islands. Mr. T. W. Vaughan, who is at present engaged upon a systematic 
study of the corals from this region, informs me that he recognises three 
species, viz. Fungia scutaria, var. verrilliana, Quelch; F. patella 
(Ell. and Sol.); and F. oahensis, Déderlein. Amongst many hundred living 
specimens collected I have as yet been unable to determine any impertant 
differences in the polyp itself. Similarly with the genus Pavia; two species 
have been identified by Verill as doubtfully Hawaiian, viz. Favia Hombroni 
(Rous.) and F. rudis, Verrill, but the living polyps show no differences of 
any significance as regards the present work. 
