612 J. E. DUERDEN. 
under adverse circumstances, and assist in getting rid of 
foreign substances which may fall upon it, but it is of much 
importance in the process of nutrition, by serving as a 
vehicle or means of conveyance of nutritive substances to the 
mouth and down the gullet. In actinians the transference 
to the mouth is largely carried out by the tentacles, but these 
organs are seen to be of much less importance in Fungia 
and Favia. The experiments have shown that nutritive 
juices reverse the ordinary outward beat of the cilia and lead 
to the production of an inhalent current; at the same time 
the nutritive substances stimulate the exudation of mucus, 
and this is then drawn down the gullet in the form of 
streams, carrying with it whatever substances are embedded 
or entangled in it. Even the transference mouthwards of 
moderately-sized food fragments, which do not become 
altogether embedded in the slime, is assisted by the same 
means. As the fragmentis moved across the disc it becomes 
more and more enveloped in mucus, and is thus brought more 
within the power of the streams already passing down the 
gullet. Further, an inhalent current being established, 
objects are ingested along with the mucus irrespective of 
their nutritive value. 
The viscid mucus also serves to entrap small living 
organisms falling or resting upon the disc, organisms 
perhaps too small to stimulate the tentacles to activity. In 
this way protozoa, small crustaceans, and larve of different 
kinds may be secured as food, much in the same way as the 
mucus secreted by the endostyle in ascidians entangles food 
particles. In addition the secretion assists the tentacles in 
their attempts to hold and secure prey of a more active kind. 
When a living annelid or crustacean is placed upon the disc 
of a coral it at once becomes entangled among the tentacles ; 
though at first wriggling violently it is soon rendered motion- 
less, and on attempting to draw the victim away with the 
forceps adhering shreds of mucus are dragged along with it. 
Paralysation and loss of motion is here mainly due to the 
poisonous action of the nematocysts, but the loss of motion is 
