530 



MERISTIC VARIATION. 



[PART I. 



pair [similarly in Position D]. MAGGI, L., Rend. R. 1st. Lomb., 

 I .ssi. xiv. |,. :;:;:>,//-/>. 



814. Homarus americanus : small cheliped as shewn in Fig. 1S2, 

 111. Il bears ..... -mal dactylopodite (D) and index (7), but this 

 I .a i-i is bent almost at rt. angles. From the outer angle arise 

 tin- part- shewn. Apparently D' and D" are a complementary 

 pair iif extra dactylopodites in Position D. The piece I' + I" 

 is imt described; from the figure it seems possible that it may 

 represent parts ,,f the indices proper to D' and D". Case given by 

 FAXON, Harv. Bull., 18801, vin. p. 261, PI. II. tig. 2. 



Cancer pagurus : right chela as shewn in Fig. 183. This is a case 

 of some conijilcxit v. The tigure will best make it clear. The daetylo- 

 podite l> is .single and so also is the index P. D is a double dactylo- 

 poditc. and ]" having teeth on two sides may be judged to be a double 

 index. But if D' and P are the normal chela they each stand opposite 



s | :, 



Fi<;. IHH. C,ui,;-i- ixiiniriix. No. 815. Rfcht cliela seen from the apex, and 

 from the outside. The lettering is aiTan.u'e.l on the hypothesis that D' is the 

 normal ila<-tylo|ic>.lite, /' tlf normal index. /* ; the double extra daetylopodite, 

 /'', siiiiill iloiilil.' extra indrx. (From /'/.. Zool. Soc.) 



the pincers to which they do not belong. Nevertheless I see no other 

 inter). relation possible. (This ease is curiously like that of the tarsal 

 claws Ln l!hl\i,-n,ii'K No. 7*11.) Specimen incorrectly described by 

 myself, /'. /.. S., L890, p. 581, iig. 2. C. 



,S 1 U. Cancer pagurus : right chela in a condit ion not far removed from 

 that of the last case, u; Si';\i';('ll.\U /In//. .S'oc. Zool. France, 18SS, p. 123, 



si7 Uca una : a chela ha\ing complex repetition of parts somewhat 



as in No. *\~>. -I \I-:CKK, <., Julirmli. </. V&r. ruhrl. .\'/ttin-k., 1851, XVII. 

 p. .'!"), PI. l.Ji'/x. 1 - and \:\. 



l'ri)i;ip-i of this natui-c i-i the case in .Ix/mv/x tlnriiitilis, I!OI:M i, v. I!OSI:NHOF, 

 /., in. Tub. i. x. n,i. -2--. 



(l>) Tit'o e.iii'ii dactylopodites arising from normal dactylo- 

 podite. 



*<Sl,s. T<> this and the next division belong the great majority of 



