Poulton.] 388 [May 16. 
iiulividuiil is attacked by an enemy and seize<l l>y the elaw, it has 
a cliance of escaping. In the case of tlie lobster, the dismembered 
claw may not let go of the enemy although the enemy may 
let go of the claw. The claw may take charge of the enemy 
while the lobster escapes. 
Now that is a very interesting adaptation. We find the claw 
so formed that it can be thrown off, but even when thrown off it 
continues to be of much use to tlie organism. Its nervous and 
muscular mechanism is so arranged that mutilation actually 
stimulates it to contract, and it continues to hold the enemy. In 
the case of certain crabs, the dismembered claws keep snapping 
and jumping about. The same is true of the tails of many lizards, 
which, when thrown off, will jumj) about in the most active way, 
distracting the attention of the enemy, while the lizard makes its 
escape. Here, too, mutilation stimulates the nervous and 
muscular mechanism in tail and claw. 
In these cases of actively used parts of the organism the 
Lamarckian interpretation is absolutely at fault. You cannot 
apply it. It is imi^ossible to explain upon the theory of the 
transmitted effects of use and disuse. No activity manifested by 
the tail after it has ceased to be part of the lizard can ever be 
transmitted. Not only that, but all development undergone by 
the tail from the effects of use and disuse, etc., up to the time of 
its severance, is also lost to the individual, and cannot be 
hereditary. And so with the claw. The large claw is the most 
important appendage of the lobster, and yet it is probable that 
most lobsters lose it many times and grow a new one. We have 
here a very specialized organ with very remarkable functions 
continuing in ever an increased degree after severance from the 
animal ; all this is readily explained by the Darwinian theory, but 
cannot be explained by the Lamarckian. 
The same inadequacy of the Lamarckian theory is forced upon 
us when we look a little more deeply into the nature of the 
process which is sujjposed to occur. The Lamarckians attempt to 
explain joints and some other structures by the effects of stress 
and pressure, but when we look into the matter a little^ we find 
that the explanation is not .so complete as it is su2:)posed to be. 
For instance, it has been believed in this country by many 
distinguished biologists that the complex shape of mammalian 
teeth is due to pressure produced by mastication. As the pressure 
