146 



BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Pinnixa faba RATHBUN, Harriman Alaska Exped., vol. 10, 1904, p. 1SS (part). 



Diagnosis. Carapace pointed at sides. Orbits pointed at outer 

 end. Dactyli of legs strongly curved. Thumb of male very short, 

 deflexed. Fingers of female gaping. Merus of third leg of male 

 twice as long as wide. 



Description. Very near faba, with which it is associated. Differs 

 as follows: Side walls of carapace less steep, and outline as seen from 

 above not longitudinally truncate, but inclined obliquely backward 

 and outward from the upper antero-lateral angle to a point on the 

 true margin above the base of the second ambulatory. Eye similar, 

 but orbit continued sidew r ays beyond it and ending in an acute angle. 



The male further differs from male of faba in having the thumb 



Pic. 89. FIXXIXA LITTOUALIS (31000), X 6. a, LEFT CHELA OP FEMALE; b, FRONT AND 



EVE IX ORBIT, FHOXT VIEW ; C, THIRD LEO OF FEMALE J d, LEFT CHELA OF MALE ; C, THIRD 

 LEG OF MALE. 



shorter, more deflexed, tip less upcurved, subterminal notch deeper; 

 dactylus more strongly curved, prehensile edge entire. Legs more 

 unequal than in faba; first leg reaching to distal third of propodus 

 of second ; second leg to dactyl of third ; fourth overlapping carpus 

 of third leg by length of dactylus; third leg noticeably stoutest, 

 merus twice as long as wide. 



The female differs from female of faba in having a little wider 

 palm, thumb a little shorter, more deflexed, and with a very shallow 

 subterminal notch, the dactylus in consequence more bent downward, 

 leaving a narrow gape. Legs more unequal than in faba, but the 

 difference is not so great as in the males of the two species. 



Variations. Immature females as well as immature males have 

 chelae resembling those of adult males that is, with the fingers 

 widely gaping, thumb short, and dactyl strongly curved. The only 



