600 
the crab was first removed from the shell — the shell being broken 
open. Then with a pair of very fine scissors the muscles just proxi- 
mal to the breaking-joint were cut in two, — the points of the scissors 
being pushed through the membrane of the joint in this region. The 
leg was then cut off at any desired level, and the crab supplied with 
a new shell. The animals were kept in clean aquaria, supplied with 
running water, and were fed daily. Some of the crabs die during the 
first two or three days after the operation, especially when one of 
the large first legs is cut off. The number of deaths is much greater 
than when the crab throws off the leg at the breaking-joint. After 
two or three weeks the crabs were killed and examined. This length 
of time is too short for regeneration to have gone very far in most cases, 
but it is long enough to show in many cases that regeneration can 
take place. In only a few instances had the crabs moulted, and it is 
only after this change takes place that the new leg increases much 
in size. 
Several cases of regeneration of the first pair of walking legs (that 
had been cut off at different levels) are shown in Figs. 1—5. In Fig. 1 
the leg had been cut off at the joint between the fourth and fifth 
segments (the first segment, i. e., the dactylopodite, being reckoned, 
as the most distal one, see Fig. 6 B for method of counting). A 
new, small leg is regenerating from the center of the cut-surface. In 
Fig. 2 the leg had been cut off in the middle of the third segment 
and a new bud has appeared that arises from the center of the 
cut-end. In Fig. 3 the cut had been made near the joint between 
the second and third segments, — a piece of the second segment 
being left attached to the stump. A bud-like outgrowth protrudes 
at the end and no doubt represents the rudiment of a new leg. In 
the next case, shown in Fig. 4, the cut had been made through the 
base of the second segment. A large bud-like outgrowth over the cut 
surface represents in all probability the rudiment of a new leg. In 
