172 ZOOLOGISCHE MEDEDEELINGEN — DEEL I. 



The length of the carapace is to its breadth as 1 : 2.20, except in the 

 smaller female, where the proportions are as 1 : 2.09 ; whereas in M. 

 dilatatus these proportions are as 1 : 2.10. 



Some dimensions of the original specimen of Cancer brevis, kindly 

 delivered by Prof. Vanhöffen, may be inserted here: 



Distance between external orbital angles . 18. — 



Length of carapace 8.5 



Length of palm (index excluded). . . . 11. — 



Length of dactylus 5.6 



Least breadth of front ....... 3. — 



M. brevis has been found at Mauritius, at Pondichéry and at Celebes 

 and Halmaheira. 



M. hilgendorfi n. n. (PI. VII, Fig. 6). 



1851. M. carinimanus Bianconi. Spec. zool. mossamb., Fasc. 5 p. 85 (Mo- 

 zambique). 



1869. „ brevis Hilgendorf (nee Herbst). Baron v. d. Decken's Reisen in 

 Ost- Afrika, Bnd. 3, Crust., p. 86, pi. 3 f . 4 (Zanzibar and Red Sea). 



1878. „ carinimanus Hilgendorf (nee Milne-Edwards). Monatsber. Ak.Wiss. 

 Berlin 1878, p. 806 (Mozambique). 



1880. „ brevis de Man. Notes Leyden Museum, v. 2 p. 70 (Bay of 

 Pasandawa, Madagascar). 



1906 „ brevis? Nobili. Ann. Sc, nat. sér. 9, Zool., t. 4 p. 318 (Red 

 Sea and Perim). 



I have already explained how Hilgendorf in 1869 referred a specimen 

 from Zanzibar to Cancer brevis of Herbst and afterwards, recognizing the 

 difference, regarded this specimen and another from Mozambique as M. 

 carinimanus. As the species of Herbst and of Milne-Edwards have turned 

 out to be identical, but do not agree with that of Hilgendorf I am obliged 

 to create a new name for Hilgendorf 's species. 



Nobili synonymises the M. brevis of Hilgendorf with M. grandidieri M. 

 Edw., as his specimens agreed very well with description and figure of the 

 first-named species and also with an original specimen of the species of Milne- 

 Edwards. I am unable to explain this discordance, unless it be presumed that 

 Nobili's specimens are referable to a transitional subspecies. The author 

 states, however, that the dactylus of the male cheliped has no large tooth, 

 which character is not referable to any of the species here named. I am inclined 

 to believe that Nobili's specimens are to be regarded as the present species. 



The differences between this and the preceding species are many. The 

 carapace is less widened, finely granulated (not provided with the large 

 granules of M. brevis and M. dilatatus) and destitute of the longitudinal 



