108 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



at about the third of the distance it disappears and is succeeded by 

 a slightly convex surface which continues proximally throughout 

 the remaining region between the dentate margins. At about the 

 middle of this convex surface arises a large sharply-pointed spur 

 or tooth. Finally, it is most important to note that at the extreme 

 proximal region of the abnormal process is a short stump D' (R+L) 

 which projects upward from the surface, and is located at the ter- 

 minous of the two rows of teeth. The form of this stump is such 

 that its posterior surface is convex, while the anterior surface facing 

 the rows of teeth is flattened. The top of the stump clearly shows 

 that it is the remnant of a larger segment which has been broken off. 

 The facts just described lead us to the conclusion that this abnor- 

 mal process is morphologically a double index; the fissure and 

 dentate margins indicate the outlines of these extra indices, and 

 the large spur between them is a double ''lock-tooth" correspond- 

 ing to the "lock-tooth" (t) on the normal index. This double 

 "lock-tooth," together with the pointed teeth and tactile hairs on 

 each index, places these indices under the category of "nipper 

 claws." Moreover, the stump at the base of these indices suggests a 

 still further morphological interpretation. For while this stump is 

 too small to furnish positive evidence as to the character of the 

 original structure, still its form and position strongly indicate that 

 it is the remnant of a former double dactyl. If this inference is 

 correct, it follows that the abnormal process of this chela is morpho- 

 logically equivalent to two extra "nipper claws." 



3. Tioo Extra Cheloe arising from the Meropodite. 



Specimen No. 5. Fig. 5 (Right Chela). 



All of the preceding abnormal chelae were studied as dried speci- 

 mens. But the next chela to be described was discovered on a live 

 lobster taken off cape Newagen, Maine. We left chela of this lob- 

 ster was a normal nipper, but on the right chela, instead of one, 

 there were three distinct claws. The animal was transferred to the 



