20 



If short pieces of the old lantern-muscles have been left attached 

 to the longitudinal muscles at the time of the operation, the ends of 

 these begin to proliferate new tissue about the time that the new lantern 

 forms, although a few specimens examined exhibited regenerated lantern- 

 muscles when no indication of a new lantern could be found. If the 

 animal had been divided just posterior to the lantern-muscles, so that 

 these had been entirely removed, a proliferation of the tissues of the 

 longitudinal muscles takes place, in the form of a bud, at a point homo- 

 logous with the position of the lantern-muscles in the normal animal. 

 In either case the new muscles grow forward in three or more separate, 

 strand-like parts, which unite into one just before union with the 

 lantern is effected. 



The reproductive organs are the last to regenerate in individuals 

 in which these organs have been extruded. This subject will be discussed 

 in a later paper. 



In Cucumaria gruhi as in Thyone hriareus regeneration takes place 

 readily in the posterior past of an animal when the anterior part con- 

 taining the lantern and nerve-ring has been removed. 



In exper. no. 1, all the posterior parts regenerated but none of 

 the anterior parts. 



When the animals were cut into three parts as described in exper. 

 no. 2, thirty- two out of forty-two posterior parts regenerated but none 

 of the anterior parts. Ten middle pieces lived four months, or until 

 killed , but , although the two cut ends were completely healed there 

 was no regeneration of organs evident. 



Among the animals which had been divided transversely into two 

 equal parts, all the posterior parts lived and regenerated. Ten anterior 

 parts remained alive until the close of the experiment, and three of 

 these had regenerated missing parts except reproductive organs. 



In exper. no. 4, three out of fifteen anterior parts regenerated a 

 new cloaca; all other anterior parts died within six weeks of the opera- 

 tion. Eleven out of the fifteen posterior parts each about 1 cm in 

 length, were living four months after the operation. In each of these 

 pieces the cut end healed, and the anterior body-wall grew forward in 

 the shape of two or more hollow protuberances which formed a body- 

 cavity anterior to the cloaca. Some of these pieces are still being kept 

 alive in order to see if a complete animal will develop from such a small 

 fraction of the whole. 



No animal cut longitudinally into two parts lived longer than a 

 week whether the organs were left in the body or removed. 



In ten out of fifteen individuals cut open along an inter-radius from 



