| OCR Text |
Show 1 9 0 5 .] FROM CHRISTMAS ISLAND. 5 4 3 of tlie chelipedes obtuse, or little pronounced, never spiniform. Fingers, in the male, with a tuft of hair on their outer surface, proximally (barbatus, pusillus), or glabrous; in the latter case the palm is either smooth on its outer side (pilipes), or granulated (intermedins). Ambulatory legs more or less hairy, no subterminal spine on the anterior border of the meropodites. Artificial key to the males of the Indo-Pacific species of the genus Ptychognathus Stimps.* 1. Fingers glabrous on their outer side (proximally+) .............. 2. 1. Both lingers, or one of them, with a tuft of hair on their outer surface, proximally...................................................................... 3. 2. Exognath of external maxillipedes, in the adult male, twice or more than twice as broad as the ischium J ...................... 4. 2. Exognath less than twice as broad as the ischium .......... 5. 4. Inner surface of the chelte glabrous .......................................... 6. 4. Inner surface of the palm with a tuft of hair ; carpus with a small, acute tooth at the inner angle; second and third anterolateral teeth of the carapace sharp, salient; epigastric lobes distinct....................................................................................... . dentatus. 6. Inner angle of the carpus obtuse or pronounced,but not spiniform; a brush of stiffish hair at the tip of the fixed finger on its outer surface; second and third antero-lateral teeth of the quite flat, much depressed carapace not salient, incon- ^ r iei-iem spicuous ..................................................................................... | andamanicus §. 6. Inner angle of the carpus produced to form a long spine; no brush of stiffish hair at the tip of the fixed finger on its outer surface; second and third antero-lateral teeth of the flat, though not particularly depressed carapace salient, sharp ... spinicarpus. 5. Two teeth behind the extraorbital angle .................................. 7. 5. One single, small tooth behind the extraorbital angle; inner angle of the carpus rounded; outer surface of the chelae smooth ; ambulatory legs with long hairs on both margins . glaber. 7. Outer surface of the chela1 smooth, towards the base of the immobile finger .......................................................................... 7. Outer surface of the chelae distinctly granulated; anterolateral teeth of the carapace as little prominent as in Ptych. riedelii, general shape of the carapace as in Ptych. pilipes, and ambulatory legs, as in that species, very hairy ............. intermedins. 8. Inner angle of the carpus produced to form a short, sharp spine.............................................................................................. 9- 8. Inner angle of the carpus obtuse ; distance between the extraorbital angles much shorter than the length of the carapace; epigastric lobes distinct; ambulatory legs very hairy .......... pilipes. 9. Distance between the extraorbital angles much shorter than the length of the carapace; epigastric lobes distinct .......... polleni. * Ptych. andamanicus Alcock is included in this key, though only the female is known, because this species is probably identical with riedelii, or in any case most ClT Th ^word " proximally " is added, because in Ptych. riedelii and andamanicus there is a small tuft of hair at the distal end of the immobile finger, externally. + Only the young female of andamanicus is known. In it the breadth of the exognath is nearly twice that of the ischium; we may therefore conclude that in thelidult male the exognath will be twice or more than twice as broad as the ischium, because, as a rule, the exognath is, in this genus, less broad m the female than m th| 1These two species are probably identical. The carpus of the chelipedes of riedelii has a tuft of hair on its outer angle, both in the male and m the female; in Alcock's description of andamanicus this character has not been mentioned. Ptych. riedelii has also been observed at Atjeh. |
