REGENERATION IN AN EARTHWORM, EISENIA FOETIDA (SAVIGNY) 1826. III. REGENERATION FROM SIMULTANEOUS ANTERIOR AND POSTERIOR TRANSECTIONS

¹ Colby College, Waterville, Maine

Regenerates from fragments were all caudal and were obtained from a region behind 30/31. Ten-segment fragments regenerated at both transections in the region between 35/36 and 60/61, at posterior transection only in the region between 60/61 and 90/91, not at all behind 90/91; producing as many segments, in homomorphic tails, as 40-segment fragments. The latter, at 35/36-75/76, regenerated at both surfaces. Heteromorphic regenerates developed later, were always smaller, and almost always differentiated fewer segments than homomorphic tails. Starvation did not inhibit regeneration posteriorly by 15-segment fragments.