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The buccal cavity and the external maxillipeds greatly resemble that of Hexapus^ but 

 the former is yet more arch-like and the surface of the latter is not hairy, but granulate; the 

 merus, however, is not oblong, but subquadrate, though with rounded angles. 



In both sexes the right chela is slightly higher and thicker than the left. Meropodite 

 of cheliped short, with sharp granules and a row of hairs along upper and inner margin ; wrist 

 short, with the inner angle produced; upper border of palm inflected inward and sharpened, 

 thus being able to produce a squeaking sound when being rubbed against the "musical ridge"; 

 fingers compressed, teeth interlocking, two of them, near the base of the movable finger of 

 the right chela, being especially large and directed obliquely-backward. 



I have nothing to add to Doflein's description of the ambulatory legs. As to the 

 sternum, it is not smooth in my larger specimens, but finely granulate and punctate, like the 

 carapace; and the segments of the abdomen of the cf are free only in the young state, in the 

 larger individuals the 3'''^ to 5'^ segment are entirely coalesced. The first segment of the 

 abdomen of both sexes is hidden under the carapace; the terminal segment in the cf is as long 

 as the preceding. As to the abdominal appendages of the cf and the sexual openings I can 

 only confirm Doflein's statements. 



The animal is of uniform ivory-white colour, without special markings. 



The "Valdivia" e.xpedition obtained a single specimen south of Nias, from a depth of 

 470 metres. Afterwards Miss Rathbun records a single, very young specimen (breadth of 

 carapace only 1.8 mm.) from the Gulf of Siam, from a depth of only 6 fathoms; on account 

 of its damaged condition the author is doubtful about identifying it with Doflein's species ^). 



Some of my specimens are larger than those of Doflein. 



Dimensions in mm. : 



9 

 8.75 



3-— 



Fronto-orbital distance .... 

 Width of anterior part of front . 

 Width of front between eye-stalks 



Length of carapace 



Breadth of carapace 



Length of left chela 



Length of right chela 



Length 



Length of meropodite along ant. margin 



Breadth of meropodite 



Length of carpo- + propodite along ant. margin 



Length of dactylus 



Posterior margin of carapace 



Base of abdomen 



of second pair 

 of walking legs 



9-75 

 1375 



8.— 



8.25 

 28.— 

 12.5 



2. — 



9-— 

 4-— 

 10.5 



3-25 



l) The front 'in the Siamese individual, though agreeing with that of Doflein's spAimen, seems to be quite horizontal, not obliquely 

 deflexed, and the external maxilliped, if correctly figured, is of an abnormal shape: the ischium is much longer than the merus and 

 presents parallel margins, the carpus is produced hood-like over the propodus and the dactylus is not longer than the preceding segment. 



95 



