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cut end of the body-wall becomes closed. The new intestine always forms 

 as a bud from one side of the old intestine, at a point near the cloaca. 

 The anterior open end of the old intestine closes forming a blind sac. The 

 new intestine grows forward as a solid rod of cells from one to two milli- 

 meters in diameter. The lumen of the new intestine, which becomes con- 

 tinuous with that of the old intestine forms after the solid growth forward 

 has become about one mm in length. As the growth in length proceeds, 

 the diameter of the intestine increases, and continues to increase after 

 the intestine has become attached to the anterior closed end of the body- 

 wall. Until union with the body-wall takes place, the new intestine is 

 a straight tube. As soon as attachment to the body-wall is effected it 

 elongates and turns on itself forming the loops characteristic of the 

 normal animal. 



The attachment of the intestine appears to be a -stimulus which re- 

 sults in two different processes in the closed oral end of the truncated 

 animal. On the one hand, histolysis of the tissues of the body-wall 

 begins directly above the lumen of the new intestine; on the other, a 

 proliferation of cells at several points near the jjlace where the 

 new intestine has become attached, forms the beginning of a new lan- 

 tern. In no single case, among the animals examined, had either of these 

 processes begun before the intestine had become united to the body- 

 wall. Histolysis begins in the eiDidermis and proceeds inwards. After 

 an opening is formed, the oesophagus and stomach are differentiated 

 from the anterior part of the new intestine. The proliferation of cells 

 which form the new lantern takes places in the region of each of the 

 radial nerves. The cut ends of the radial nerves enlarge so that each 

 end has a knob-like appearance. This enlarged end grows downward 

 into the proliferated tissue which projects downward into the body-ca- 

 vity. The proliferating masses unite thus surrounding the intestine. As 

 the radial nerves grow downward they are accompanied by blood and 

 water-vessels which are differentiated out of the new tissue formed at 

 the extremities of the old vessels, with which the new are continuous. 



The »Anlagen« of the various parts of the lantern, such as the 

 tissues destined to form the calcareous plates, are laid down early in its 

 development. Buds from the radial nerves unite to form the ringnerve. 

 Budding and union of the radial vessels leads to the formation of the ring- 

 vessels. The Polian vesicle, the stone-canal, and the vessels which supply 

 the tentacles, are the latest formed of the organs related to the lantern. 

 As a consequence, tentacles do not appear until the regeneration of the 

 lantern is nearly complete. All the tentacles are not formed at the same 

 time ; or, it may be that their growth is unequal for one or two first ap- 

 pear, then others are added until the normal number is complete. 



