DESCRIPTION OF AN ABNORMAL LOBSTER CHELIPED. 



257 



The arrangement of certain of the spines also goes to show that 

 d.p' . is to be considered as the equivalent of a double dorsal 

 articular process corresponding to the doubled abnormal claw; 

 but there is no need to go into the details of this matter, which 

 can be made out in the figures. 



Meropodite. — Here, too, the abnormality is evident. The joint 

 is relatively much thicker than the corresponding joint in a 



FL 



—D'L 



Fig. 4. Normal left cheliped of 

 a lobster, seen from posterior side 

 (really a little ventro-posterior). 



normal lobster. The normal plane of articulation between the 

 meropodite and the carpopodite is morphologically horizontal, 

 the articular processes therefore being anterior (Figs. 3 and 4, 

 a.p^ and posterior {p.p.). These processes and the articulation' 

 are essentially normal in the abnormal claw, but in the concavity 

 of the (morphologically) ventral side is a large process {p') which 

 apparently represents one point for an incipient axis of articu- 



