198 ZOOLOGISCHE MEDEDEELINGEN — DEEL I. 



upper surface of the dactylus is smooth, not granular, and the index 

 has no large tooth, but is coarsely denticulated at the cutting margin and 

 not curved downward. In both species here named the mobile finger 

 has a large rectangular tooth near its base. 



The ambulatory legs of M. depressies are remarkable for their mas- 

 sivily-built meropodites in the middle pairs of legs; these meropodites have 

 convex anterior and posterior margins and their thickness is more than 

 one-third the length, in the case of the first to third pair there is a 

 distinct spine at the anterior margin, at the usual place. Mero-, carpo- 

 and propodite of the second and third pair of' ambulatory legs are densely 

 clothed with hairs, both at the upper and under surface (only in the 

 second pair the carpo- and propodite are naked at the under surface). 



This species which ranges throughout the whole Indian Ocean, though 

 it has not as yet been found at the east coast of Africa, is represented 

 in the Museum by several specimens: four (3 <ƒ, 1 9) fr° m Djeddah a t 

 the Red Sea, already spoken of by de Man (1881), one (cf , dried) from 

 an unknown locality (found by me in a lot of M. japonicus, but certainly 

 erroneously associated with that species, as both have never been recorded 

 to occur in the same localities) and finally four (all Q, dried) from the 

 Red Sea and received as co-types from Rüppell himself. 



The dimensions of the largest specimens at my disposal are 



1 2 



c? 9 



Distance between external orbital angles 19.5 29. — 

 Greatest breadth of carapace (at the 



middle of the lateral margin of the 



antero-lateral teeth) 20.5 30.5 



Length of carapace 14. — 20. — 



Least breadth of front 2.5 (scarcely 2.5 (much con- 

 constricted) stricted). 



The species may be in some cases more transversely elongated, for 

 Alcock mentions a specimen, the length of which is the same as in my 

 male specimen, but with a carapace-breadth of 22 mm. 



M. definitus Adams & White. 



1847. M. definitus Gray. Cat. Crust. British Museum, p. 37 (Philippines). 



1848. „ definitus Adams & White. Zool. Yoy. „Samarang", Crust., p. 51 



(Philippines). 

 1894. „ depressus Ortmann, nee Rüppell. Zool. Jahrb. Abt. Syst., Bnd. 7 

 p. 745 (locality unknown). 



