THE BEHAVIOR OF THE SHORE-ANEMONE 323 



beef juice. Injection with a strong sodium chloride solution 

 seemed to alter in no way the normal responsiveness of the 

 animal either to food or to contact. The animals used in these 

 experiments were first tested to see that they would take food 

 before the experiment was performed, with the result that they 

 immediately availed themselves of the opportunity. In fact, 

 I have yet to see an anemone of this species in an expanded 

 normal condition in their native habitat refuse to accept food; 

 for they all appear to be in a condition of quick responsiveness 

 to stimuli of the various kinds. 



ROLE OF MUCUS SECRETION 



Duerden (1906) in a most interesting paper on the role of 

 mucus in corals has shown that it serves two general functions. 

 (1) The protection of the polypal surface from foreign objects 

 and in keeping it clean, and (2) the entanglement and ingestion 

 of prey and food substances. He notes that nutritive substances 

 and extractives placed upon the polyp increase the amount of 

 mucus exuded. The same result is secured, though to a less 

 degree, by mechanical stimulation. He says : " Not only does 

 the mucus serve as a protection to the polyp under adverse cir- 

 cumstances 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." 



Perhaps the role of mucus in the actinian polyp is not essen- 

 tially different to that played by it in the corals. The idea of 

 Pavlov (1910) quoted in a preceding paragraph to the effect 

 that the secretion of mucus in the stomach of the dog upon the 

 application of potent reagents is protective in that it dilutes or 

 neutralizes the noxious substance is certainly suggestive in its 

 application to the results secured in Cribrina. We must con- 

 clude, I believe, that the copious exudation of mucus upon the 

 application of such substances as potassium chloride and mer- 

 curic chloride serves in a decidedly protective manner. I have 

 too little evidence to say to what extent the mucus acts as a 

 food securing factor. In the extruded material of the anemones 

 examined, many smaller organisms were found, and it is quite 

 possible that these might accumulate in the mucus film always 

 over the surface of the anemone until they had acquired a 



