COLLECTED IN DUTCH NEW GUINEA. 309 



(a) Aru Islands. 1 male. 



This specimen differs from Dr. Eoux's type chiefly in the disposition of the epigastric 

 lobes, which are rather more oblique and extend forwards nearly to the line of the 

 posterior orbital margins. The carapace is relatively a little narrower and deeper, 

 the front wider, and the horizontal frontal ridge extends nearly the whole width of the 

 front, instead of being distinct only for a short distance in the middle, as in the type. 

 The dactylus of the larger cheliped is slightly less arched and more distinctly dentate. 

 The abdomen is not quite so narrow as in the type, and the sixth somite is hardly 

 wider at its distal end than at its proximal end. 



(b) Mimika River. 7 males, 2 females. 



As regards the direction and position of the epigastric lobes, these specimens agree 

 rather better with the type than with the Aru specimens described above. They 

 differ from both in the greater depth of the carapace, which is never less than twice as 

 wide as it is deep, although most of the specimens are relatively narrower, in pro- 

 portion to length, than the type. The dorsal surface is rather more convex, both from 

 before backwards and from side to side, and the antero-lateral portions of the cervical 

 groove are inclined at a more acute angle to each other. The frontal ridge is well 

 defined and extends the whole width of the front, which is, in most cases, distinctly 

 narrower than in the type. In a large male the fingers of the larger chela gape even 

 more widely than in the type, but are very similar in form and armature. In some of 

 the males the abdomen resembles that of our specimen from the Aru Islands, in others 

 it is more like that of the type, the sides being more concave and the penultimate 

 segment distinctly narrower at its proximal end. 

 (c) Utakwa River. 2 males, 1 female. 



These specimens differ considerably from all those discussed above, especially in the 

 greater length of the walking-legs, those of the second pair being more than twice the 

 length of the carapace. The carapace is rather more convex anteriorly, but flatter 

 behind and also from side to side, with the inter-regional grooves better marked ; near 

 the antero-lateral margins it is much more rugose. The epigastric lobes are obscure, 

 transverse, and rugose. The front is inflected towards the epistome, but the transverse 

 ridge thus formed is much less sharp than in the specimens described above. The 

 larger of the two males has the palm of the larger chela inflated, the fingei's gaping at 

 the base, and somewhat feebly toothed, the whole suggesting that a better-grown male 

 would have a chela of the aruana-type. The abdomen of the males resembles that of 

 the type. 



The specimens of this group approach, in the greater relative length and slenderness 

 of the walking-legs, the specimens of P. wollastoni which were collected along with 

 them. They differ from them, however, in practically all the other characters enume- 

 rated below as distinguishing that species from P. aruana. It is possible that they 

 ought to be held as distinct from P. aruana, but in the absence of more material I 



2u 2 



