's RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN 163 



narrowness of the carapace, the length of which is two-thirds its greatest 

 breadth. The external orbital angle projects straightly outward and is 

 spiniform but somewhat depressed; the two lateral teeth behind it are 

 much smaller. Nobili has observed the same form of these teeth in his 

 specimens. At the lateral margins of the carapace the fine denticu- 

 lations (behind the antero-lateral teeth) which are so conspicuous in the 

 preceding species, are here represented by a series of very minute beaded 

 granules, though Souleyet mentions in his species, M. podophthalmus, a 

 series of „dentelures très-fines qu'on n'aperçoit que difficilement à cause 

 des long poils qui garnissent les côtés de la carapace". The whole surface 

 of the carapace is nearly smooth, the various grooves are faintly indi- 

 cated, those circumscribing the cardiac region even being absent, the 

 front is less deflexed than in M. transversus, and the carapace itself is 

 evenly rounded, not abruptly sloping at the sides, where only with the 

 aid of a magnifying-glass very small granules may be observed. 



The cheliped of the male has a high and short palm ! ), provided with 

 a rather strong ridge parallel with the inferior border, but continued more 

 conspicuously to the tip of the immovable finger. This ridge is already 

 mentioned by Owen and Souleyet and also shown in Miss Rathbun's 

 figure of the male cheliped ; but whereas Souleyet rightly remarked that 

 each of the fingers carries a larger denticulated tooth at the cutting 

 margin, such a tooth is not figured by Miss Rathbun at the movable 

 finger. Though the authoress had only young males at her disposal she 

 supposed that Milne-Edwards' figure of the cheliped was taken from a 

 female specimen, as in this figure no teeth at the fingers are shown. 

 In my adult females however the fingers are comparatively much longer, 

 more slender and the palm is compressed and much less high than in 

 the figure of Milne-Edwards; the rim near the under side of the palm 

 is more conspicuous than in the male. 



The meropodites of the ambulatory legs have no spines at the posterior 

 border; carpo- and propodite of the penultimate pair are not distinctly 

 longer than those of the preceding pair. 



The Museum contains in all five specimens of this species, two adult 

 females and three very young males, collected at Djeddah (Red Sea). 



The species has a wide range, extending from the Red Sea along the 

 islands of British India and the Gulf of Siam to the Loo-Choo-isles, 

 Australia and the Sandwich islands. It does not seem to have been found 

 however in the Netherlands' East-Indies nor at the coast of East- Africa. 



I give here the dimensions of some specimens in mm. 



1) At least in young specimens; the adult males snow, according .to Nobili, a much longer 

 palm, more than twice as long as the immobile finger. 



