My study of the regeneration of the earthworm, Allolobophora foetida, bdgan in the spring of 1892. The results of this work, extending" through the winter of 1893--94 were published in the Quarterly Journal of Microscopical Science, XXXVII. 1895. During the winters of 1895--96 and '96--'97 I carried out some further experiments which were descl:ibed in Roux's Archiv. V. 1897. Since then I have carried on, during each collegiate year, additional experiments extending over the four yea r s between 1898--1902. Two of the principal results, that I have obtained, have been briefly described, the one in the Anatomischer Anzeiger. XV. 1899, and the other in my book oll >>Regenerations< 1901. page 53. The following pages give a complete account of the experiments of the last four years.