REPORT OF COMMISSIONERS OF INLAND FISHERIES. 107 



The remaining proximal segments of this chela appear practically 

 normal, except that they are rather thick and stubby: — The third 

 segment or carpopodite (c), especially, is unusually broad and mass- 

 ive. The carpopodite is also marked by a transverse groove or 

 indentation on its dorsal surface (not shown in the drawing), which 

 appears as if the limb had been pinched or sharply flexed upon itself 

 at some time when the chela was in a more plastic condition. 



b. Two Extra Indices and Double Extra Dactyl. 



Specimen No, 4. Fig. 4 (Right Chela). 



In this chela it is evident that the parts I and D are the normal 

 segments of the claw. The dactyl (D) is in normal condition, except 

 that a small part of the tip has been broken off. The propodite is 

 also apparently normal in all parts, except the region in which the 

 abnormal structures about to be described have arisen. The toothed 

 borders of the index and dactyl present the dentition and tactile 

 hairs characteristic of a true "nipper" claw. 



Upon the outer border of the index is a large and prominent 

 abnormal process, IL and IR. This abnormality takes its origin 

 from a region rather intermediate between the morphologically 

 posterior and ventral surfaces, but arising more directly posteriorly 

 than ventrally. It is about half the length of the normal propodite, 

 and at its greatest width it is much broader than the normal index. 

 Beginning at the distal extremity of the process, and at right angles 

 to the plane of the drawing, is a deep fissure (f ) , which extends some 

 distance posteriorly and separates the tip of the process into two 

 distinct parts. Along each side of this fissure and parallel with it 

 is a slight ridge dentated with a row of pointed teeth. These two 

 dentated ridges continue in a parallel direction beyond the fissure 

 and extend almost to the proximal end of the process. On the 

 outer side of each row of teeth are tufts of tactile hairs. It has 

 already been implied that the fissm-e which separates the distal 

 tips does not extend far down between these two dentate ridges; 



