REPORT OF COMMISSIONERS OF IXLAXD FISHERIES. 119 



ate. By the time this regenerating leg had attained a length of 

 9 mm. (August 28), my attention was attracted to an unusual bud- 

 like process on the regenerating limb. Figure 19, drawn three days 

 later (August 31), shows the location of this abnormal protuberance 

 (b) on the basal segment or ischiopodite. The general appearance of 

 this protuberance suggested that it might be the beginning of another 

 extra limb, similar to specimen No. 7; but this did not prove to be 

 the case, for instead of growing larger, this abnormal bud begun to 

 decrease in size, and by September 9 it had almost entirely degener- 

 ated and disappeared. 



The lo])ster in which this abnormal phenomenon appeared was an 

 8-inch male specimen which was being used in an experiment on the 

 regeneration of the abdominal appendages. After the extra bud 

 just described had degenerated, I cut off the regenerating leg just 

 above the basal segment, to see if the degenerating bud might be 

 made to grow again; but no result was obtained, because the entire 

 stump was finally dropped. 



b. A Double Regenerating Papilla. 



In another lobster two regenerating papillae (pp. 1, pp 2) were dis- 

 covered, as shown in figure 20. These two papillae were in the stump 

 of the second right leg from which the limb had been autotomously 

 removed on July 26. When these two protuberances were first 

 observed (August 18) they were about 2^ mm. in height; the inner 

 one (pp 1) being slightly the larger. At first it was anticipated that 

 these papillae might develop into two limbs, but this did not occur. 

 The growth of the outer bud became retarded and it increased but 

 little more in size (see Fig. 21), while on the other hand, the inner 

 bud grew at the usual rate and finally differentiated into a normal 

 thoracic leg. 



In both the above cases it seems at least a plausible suggestion 

 that some of the regenerating cells may have been temporarily 

 shunted off in an abnormal direction from the direct course of 



