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 chelz 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 off. The chehylitg carries 6 or 7, acute, 
conical teeth, and the fixed finger 4 or 5, which are a little lar eer. 
These slight differences 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, the exognath 
(PL. XVII. fig. 3) appears a little broader than the ischium, the pro- 
portion 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 margin, 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 mner border and 
posteriorly, as is also the endognath, except in the middle, and 
short stiff sete are inserted on the puncta. The abdomen (fig. 4) 
resembles that of Ptych. polleni de M. from Madagascar (de Man, 
l.c. Taf. 28. fig. 20 6), as is proved by the figure and the measure- 
ments. Sternum and abdomen are punctate; the 3rd, 4th, and 
5th segments of the abdomen, counting from the base, carry, 
moreover, 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 carries one or two short, stiff sete. The upper 
border of the merus is hairy 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 pune- 
tate, the rest smooth, but it appears finely granular under a 
lens in the female; the internal angle is obtuse, though not 
rounded. The chele (fig. 5) resemble closely those of Ptych. 
barbatus, not only as regards their general shape but also because 
