1905.] FROM CHRISTMAS ISLAND. 539 



the fingei's are provided, each, exactly as in that species, witli a 

 tuft of hail' ; the chelae also much resemble those of Ptych. pilipes 

 A. M.-Edw. from the Philippine Islands, but here the tufts of 

 hair are wanting. Measured horizontally, the chelae appear just 

 as long as the distance between the antero -lateral angles of the 

 carapace ; the palm is a little shorter than the fingers and, at their 

 articulation, a little higher than long. The convex, outer surface 

 of the palm, under a lens, appears very finely, but closely, punctate, 

 though smooth to the naked eye ; both the upper and the lower 

 borders are rounded. The somewhat curved, tapering dactylus 

 carries 7 or 8 small teeth, which are rather obtuse, except two or 

 three near the tip ; the immobile finger has 5 or 6 more conical 

 teeth, which are larger than those of the dactylus, especially two 

 or three in the middle. The fingers are finely and closely punctate, 

 just like the palm ; on the middle of the outer surface of the 

 fixed finger the puncta are arranged in a longitudinal row that 

 extends fi'om the tip almost to the middle of the palm ; a few 

 larger, impressed puncta occur on the distal half of the index just 

 above that row. As in Ptych. barbatics, each finger carries a close 

 tttft of broion ivoolly hairs on the proximal half of its outer sui'face ; 

 the tuft of the dactylus does not extend on to the upper border 

 of the finger, and that of the fixed finger reaches only halfway 

 between the teeth and the lower border. The tips of the fingers 

 have horny margins : on the outer side of the tip of the fixed 

 finger, close to and parallel Avith the horny edge, are seen a 

 few short, stifiish seta?, though much less numerous than in the 

 female ; on the tip of the dactylus they are perhaps woi-n off. 

 The inner surface of the chelas (palm and fingers) is smooth and 

 glabrous. 



The ambulatory legs ai-e hairy on the upper side of their basal 

 joints, and a few stiff setae occur on the lowei' sui'face of ischium 

 and merus on either side of the articulation between these joints ; 

 the posterior border of the last two joints is also setose, and rows 

 of short setae occur on the lower side of the propodites of the 1st 

 and 2nd pair. For the rest, the upper and the lower borders of 

 these legs are glabrous, devoid of the long hairs that are character- 

 istic of Ptych. pilipes A. M.-Edw. The meropodites appear under 

 a strong lens very finely granular, except those of the last pair, 

 which are almost smooth and only punctate ; the puncta are 

 small and numerous, but three or four larger puncta in a longi- 

 tudinal row are found on the middle of the meropodites of the 

 last pair. Just as in Ptych. bat'batus A. M.-Edw., there is 710 

 subterminal spine on the anterior border of the meropodites. 

 The following joints are also punctate, and the dactyl i are ridged 

 longitudinally l3oth on the upper and lower sides. 



On a yellow ground-colour the upper surface of carapace and 

 legs is marked with innumerable, small, irregular spots of a dark 

 purple colour, which on the epigastric and protogastric regions 

 are almost confluent. 



Among the twelve species of Ptychognathus, certainly Ptych. 



