538 DR. J. G. DE MAN ON CRUSTACEANS [Dec. 12, 



The female from Christmas Island is of a somewhat larger size 

 than Heller's type specimen ; the measurements are the same, 

 except that the greatest width of the carapace of the female 

 from Christmas Island is a little larger in proportion both to 

 the length of the carapace and to the distance between the 

 external orbital angles. The exognath of the external maxil- 

 lipedes, though still less broad than the ischium- joint, appears 

 broader in proportion to this joint than in Heller's younger 

 type specimen, and the chelae are comparatively larger. The 

 tips of both fingers carry some stiffish hairs on their outer surface 

 close to the horny border ; these hairs are more numerous on the 

 tip of the fixed finger. In the Vienna type specimen these hairs 

 were, no doubt, worn ofi". The dactylus carries 6 or 7, acute, 

 conical teeth, and the fixed finger 4 or 5, which are a little larger. 

 These slight difterences are caused by the larger size of this 

 specimen, which, for the rest, fully agrees with Heller's type. 

 The male is larger than the female and more than once and a half 

 as large as Heller's type specimen ; regarding the proportion of the 

 measurements of the carapace, the male agrees with the female 

 from Christmas Island. The cephalothorax also fully agrees in its 

 other characters with my description of 1895, except as regards 

 the outer footjaws. I suggested in that paper that, in the male, 

 the exognath should be as broad as or perhaps even a little broader 

 than the ischium-joint ; this supposition is now confirmed by the 

 male from Christmas Island. In this male, indeed, tlie exognath 

 (PI. XVII. fig. 3) appears a little broader than the ischium, the pro- 

 jDortion between them being as 11 : 10; the exognath is distinctly 

 convex longitudinally and also a little transversely. The merus- 

 joint fully agrees with that of the type specimen, its antero- 

 lateral angle being rounded, whereas the external mai-gin, so far 

 as it is contiguous to the exognath, appears very slightly concave ; 

 the outer half appears, under a lens, finely granulate. The 

 exognath is somewhat punctate, except on the inner border and 

 posteriorly, as is also tlie endognath, except in the middle, and 

 short stiff setse are inserted on the puncta. The abdomen (fig. 4) 

 resembles that of Ptych. poUeni de M. from Madagascar (de Man, 

 I. c. Taf . 28. fig. 20 h), as is proved by the figm-e and the measure- 

 ments. Sternum and abdomen are punctate ; the 3rd, 4th, and 

 5th segments of the abdomen, counting fi'om the base, carry, 

 moreovei', each a larger pit on their antero-lateral angle and 

 another on the anterior half at either side of the middle line. 



The chelipedes are equal (fig. 1). The punctate, anterior surface 

 of the ischium cari'ies one or two short, stiff sette. The upper 

 border of the merus is haiiy on its proximal half, the obtuse 

 anterior border is granular and a little pubescent proximally. 

 The upper surface of the carpus is closely, but finely punc- 

 tate, the rest smooth, but it appears finely granular under a 

 lens in the female ; the internal angle is obtuse, though not 

 rounded. The chela? (fig. 5) resemble closely those of Ptych. 

 barhatus, not only as regards their general shape but also because 



