Some Pliciiotnena of Regeneration in I.ininoflrilua and related Forms. 3^7 



were removed and the first four were cut from 20 others. On June 

 22nd, 4 of the first set had regenerated a small amount of new tissue, a 

 mouth etc. and by July 17th, 4 others had done the same. The 

 romaiuder did not regenerate. Of the second set 14 had regenerated a 

 mouth etc. and one segment of new tissue by June 12th. The rest 

 died. Nene of this series regenerated more tissue although kept several 

 weeks longer. 



4th Series — April 6th 08. Three sets of ten individuals were 

 taken, three anterior somites being removed from the first set, two 

 from the second and one from the last. Of the first set eight regenerated 

 a mouth etc. and one to one and a half segments of new tissue by 

 April 20 th; two died. Six of the second set regenerated one new 

 segment by April 13th and the rest were lost. All of the last »et 

 regenerated the missing portion by April 13th. As before none of this 

 series regenerated more tissue even after several weeks. 



The tabulated results follow. In this table only those indivi- 

 duals in which an oral opening had been formed will be put in the 

 column of regenerated individuals. 



From this table it can be seen that a head is not formed when 

 more than seven somites have been removed and that even then, in 

 the vast majority of cases, a head does not regenerate. Likewise 

 when five and six somites are removed only about one half of the 

 individuals regenerate. An interesting point brought out is the small 

 amount of new tissue regenerated. None of the worms replaced more 

 than one and a half segments, which was the case when the first three 



