534 



MERISTIC VARIATION. 



[part I. 



(c) Two extra indices arising from a normal index. 

 *823. This again is a fairly common form, though much less frequent 



pi 



Fig. 189. I. Right chela of Homarus americanas. R', L', right and left extra 

 indices not separated from each other. (After Faxon.) II. Homarus vulgaris, 

 right chela in Brit. Mus. III. H. vulgaris, right chela bearing extra double index. 

 R' and L', not separated. (After Lucas, I. c.) 



R' V 



i. n 



Fig. 190. I. Left chela of Carcinus mcsnas, indices only shewn, d, place of 

 articulation of dactylopodite. In Coll. Surg. Mus. II. A similar case in 

 Homarus americanus, after Faxon. L, normal left index. R', L' y extra right and 

 left indices. 



