38 



C. M. CHILD. 



folded over much more sharply on the more distal portions o> 

 the oblique end than on the more proximal. At all events the 

 obliquity of the disc affects the rapidity of tentacle-formation in 

 some manner, and the suggestion that local differences in internal 

 pressure resulting from the different relation between the internal 

 currents and the body-wall on different parts of the oblique end 

 are concerned in producing the result observed seems at present 

 to account for the facts. The question as to whether localized 

 internal pressure is a factor in the localization of tentacles will be 

 considered elsewhere in connection with certain experiments on 

 another actinian. 



One other series of experiments in which the plane of section 

 of the body was very oblique deserves brief mention. In this 

 series the plane of section extended from a region near the orig- 

 inal tentacles on one side to a point con- 

 siderably below the proximal end of the 

 oesophagus on the other (cc, Fig. i). The 

 margin of the body-wall and the oeso- 

 phagus united down to the proximal end 

 of oesophagus, but since the cut extended 

 a considerable distance beyond this point, 

 there remained an opening of consider- 

 able size, which could be closed only by 

 approximation of the margins of the 

 body- wall and the formation of new tissue 

 between them : this, however, occurred 

 very slowly. The result of the opera- 

 tion was then at first a piece in which 

 one side of the body-wall in the oesophageal region and to a 

 point some distance proximal to it, and one side of the oesopha- 

 gus were removed. 



The distal portions of these pieces underwent considerable de- 

 crease in length so that the obliquity of the oral end was reduced. 

 In earlier stages distension with water was impossible because of 

 the opening below the tLSophagus, and tentacle-formation was 

 much delayed. Later the most distal portion bent over and to- 

 gether with the slime secretion effected a provisional closure 

 (Fig. 12), and some degree of distension took place and was fol- 



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