240 Proceedings of the Royal Society of Edinburgh. [Sess. 
(2) Division of the flexor muscle of the third (the one attached to 
the ring which actually breaks off) has the same effect. 
(3) Cutting of the nerve-cord to the tail also prevents it. 
(4) Cutting of the nerve to the limb as it leaves the gangliated cord 
prevents it. 
(5) Division of the ventral nerve-cord above the segment from which 
Stages in autotomy of a lobster’s walking-leg. a is the autotomising muscle, h the detached ring of the 
third limb-segment, and /the breaking- furrow. 
Fig. 10. — Contractions of the extensor muscle of the second limb-segment produced by 
single induced shock. Time in secs. 
the limb is innervated makes autotomy more easy {i.e. removal of cephalic 
influence). 
The process can be further studied as follows : — The tendon of the 
extensor of the second segment is cut and its end attached to a heart 
lever, the lobster being placed on its back on a frog-board. A record of 
the contraction when the limb is stimulated by induced faradic current 
shows a latent period of T4 seconds and presents the appearance shown 
in fig. 10. 
The tail, or properly speaking the abdomen, which flaps violently after 
each cut or electrical stimulation, can also be connected up to a lever, and 
a record of its contraction made along with the contraction of the extensor 
