88 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



EXPERIMENTS. 



In the discussion of the experiments and observations it has seemed 

 most convenient to arrange the data under the following subjects: 



I. The power of regeneration throughout the organism. 

 II. The relative powder of regeneration at different levels in the 

 thoracic appendages. 



III. The attainment of the normal length of the appendages. 



IV. The effect of repeated removal of an appendage. 

 V. Regeneration and the process of moulting. 



I. The Extent to avhich the Power of Regeneration Ex- 

 tends Throughout the Organism. 



Naturally in examining a lobster in search of regenerating struc- 

 tures we w^ould look at those organs which are most liable to injury. 

 Our examination would soon make it evident that among the parts 

 most exposed to injury are such appendages as the antennae and legs, 

 and it is, indeed, in these appendages that the regenerating structures 

 are most commonly seen. 



Chelipeds and Ambulatory Appendages. — In order to obtain a 

 conception of the normal conditions under which regeneration usually 

 occurs in these appendages, a few words will be necessary in regard 

 to the process of autotomy. 



The chelipeds (big claw) is divided into seven parts or segments. 

 All these segments are united by flexible joints with the exception of 

 the second and third basal segments (Plate XXII, Fig. 1), the basiopo- 

 dite (3), and ischiopodite (2). In the case of the cheliped the basiopo- 

 dite, and ischiopodite are fused together into one immovable piece, 

 lout there is still a distinct groove marking the two segments (Fig. 

 I, 1.). It is always precisely at this groove that separation occurs 

 when the limb is thrown off Iw autotomy. Fig. II shows the basi- 

 opodite (3) and the ischiopodite (2) separated by autotomy at this 

 groove or breaking plane (1.) Upon examining the broken surface 



