148 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



I have also casually examined many thousands of young "fry" as 

 they were being individually counted and taken from the hatching 

 pools during the hatching season, but I did not find a lobster with 

 double limbs. 



2. That the Great Majority of these Deformities are also Found only 

 on the More Distal Segments of the Limbs. 



In some sixty-five cases of abnormal chelae recorded by Bateson, 

 all but three of these deformed parts are found on the two distal 

 segments of the appendage. It will be recalled that Bateson con- 

 sidered one difficulty in the regeneration theory to consist in the fact 

 " that when the limb of a crab or lobster is injured it is usually thrown 

 off bodily;" although it should be observed that he hastened to add 

 that " since, according to Heinekin, such mutilated parts are some- 

 times retained, this must not be insisted upon" (p. 526). Now it is 

 quite true that when the limb is injured the whole appendage may be 

 autotomotisly thrown off, but this requires an important qualification; 

 for whether the limb is always thrown off or not depends upon the 

 character and location of injury. In some experiments on regenera- 

 tion ('05) I had occasion to mutilate the limbs of lobsters at different 

 levels of the appendages. In the course of these mutilations I found 

 that if the cheliped or leg was crushed by a pair of tweezers the whole 

 limb was almost invariably autotomously dropped, practically regard- 

 less of the region of injury. But by the exercise of considerable care 

 it was discovered that if the tip of the limb was cut off with a quick, 

 sharp stroke, the remainder of the appendage was usually retained. 

 On the contraiy, however, if the cut was made near the base of the 

 appendages, say in the region of the ischiopodite and meropodite, 

 the remaining stumps were usually dropped. Furthermore, I have 

 since found that the same conditions also hold true for regenerating 

 buds; if the buds are injured near the tip the remaining structure is 

 much less likely to be dropped than if the injuries are made in the 

 proximal regions. In view of the fact, therefore, that in proximal 



