180 ZOOLOGISCHE MEDEDEELINGEN — DEEL I. 



the breadth of the carapace. l ) For further particulars I may refer to 

 de Man's accurate and elaborate description. 



This author has also given a full account of the inferior orbital 

 margin, which, owing to the presence of a „musical ridge" in the male, 

 is peculiarly modified. De Man says (1888, p. 127): „the inferior orbital 

 margin presents in its middle a broad, though little prominent, slightly 

 triangular lobe, which is directed somewhat downward, its obtuse tip 

 being found at the internal or median side ; the upper surface of this 

 lobe is slightly concave. Behind this lobe, the inferior margin of the 

 orbits presents a second, also obtuse, much smaller lobule, which is found 

 at the external end of the under margin ; whereas the internal or median 

 part of the under margin, lying between the larger middle lobe and the 

 epistome, is armed with a row of seven or eight minute rounded gra- 

 nules, the external one of which is the largest, whereas the others suc- 

 cessively decrease in size towards the epistome, ». e. towards the inner 

 end of the orbital margin". De Man rightly remarks, that this structure 

 of the inferior orbital margin distinguishes this species very well from 

 the nearly allied M. quadratics. 



The chelipeds of my only male specimen were equal (according to 

 de Man they are sometimes unequal in size). The musical crest at the 

 middle of the inner margin of the short, triquetrous arm is obliquely 

 parallel with this border 2 ). The palm is much compressed, smooth, hairy 

 at the inner surface, crenulated at the upper margin, and without crest 

 externally; there is a faint crest however running from the tip of the 

 index to the palm, where it soon disappears. According to de Man the 

 length of the palm (index not included) is in proportion to its greatest 

 height, at the articulation with the dactylus, as 15:11, and I found the 

 same proportion, though in my specimen the palm was comparatively 

 much smaller (see the dimensions below). De Man also states the spine 

 at the inner surface of the palm near the carpal end, which is charac- 

 teristic in this species. The fingers are short, with a rather wide gap 

 between their bases, and with horny, excavated, hairy tips; the dactylus 

 has a small rectangular tooth at the base and the index a much larger 

 one, rising slightly above the general level of the cutting margin and 

 occupying nearly the whole distal half of the latter. 



The middle pairs of the ambulatory legs have very massivily built 

 meropodites with an extremely small spine near the distal end of the 



1) de Man wishes it to be understood, that he takes here the distance between the external 

 orbital angles 



2) Alcock states the same, whereas the musical ridge of de Man's specimens seems to be 

 exactly parallel with it. 



