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Gastric region of carapace with small granular points, few in 

 number and prominent. Postorbital spine absent, only a 

 granulate projection. Chelipeds short and bulky. Propodites 

 of walking legs much depressed, broader than carpopodites M.platychehs H. Milne-Edwards x ) 



i. Mictyris longicarpus Latreille. 



Synonymy and description : ALCOCK, Journ. As. Soc. Bengal, v. 69, prt 2, 1900. 



Stat. 131. Karakelang, Talaut Islands. Reef. 8 sp. 



Stat. 231. Ambon, reef. 3 sp. 



Stat. 323. Bawean Island, Java Sea. Reef. 1 sp. 



Alcock's description agrees exactly with all the specimens from different localities, in 

 the Leiden Museum. 



On examining de Haan's original specimens of M. defiexifrons") I came to the conclusion, 

 just like de Man 3 ), that this species is identical with M. longicarpus, the only difference con- 

 sisting in the occasional very faint development of the postorbital spine. That the strong spine 

 at the inner margin of the ischiopodite is nearly obliterated or wholly absent in the Q has been 

 noticed already by Alcock. To complete the description of the latter I only remark, that the 

 inner surface of the palm of the cheliped is provided with a short, longitudinal ridge. 



We may safely assume that Stimpson founded his M. brevidactylns 4 ) on specimens that 

 really were nothing than the common M. longicarpus. 



The name of Latreille's species has been sometimes spelled longicarpius and longi- 

 carpis, but Latreille in his first description used the orthography longicarpus. 



That the species has much the same habits as Uca and is likewise gregarious at suitable 

 localities appears from the following interesting passage in R. Semon's fascinating book 6 ) : "On 

 sauntering about the sandy beach before my house, I often perceived, that during ebb-tide the 

 sand was by no means smooth, but covered with millions of tiny star-shaped heaps of sand. 

 In the centre of each little heap I remarked a small canal, leading into the ground and serving 

 as a lodging to a tiny crab Mictyris longicarpus. While the water covers the beach, the crab 

 remains below the surface. Hardly, however, has the shore become dry, than it will pop up, 

 throwing out the sand above its hole and chewing it to infinitesimal particles in search of tiny 

 organisms imbedded in it. As thousands and millions of little crabs pursue this occupation at 

 the same time, the coast soon has the appearance of being prettily and carefully raked, like 

 a well-kept garden". As to the manner of feeding it is remarkable .that the fingers of Mictyris 

 end acutely and are apparently not so well adapted to the purpose as is the case in genera 



1) Ann. Sc. Nat. (3) t. iS, 1852, p. 154. Targioni-Tozzetti, Crost. Viag. "Magenta", 1S77, p. 186, pi. 11, fig. 6. Stimpson, 

 Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 103, pi. 13, f. 5. 



2) Faun. Japon., Crust., 1835 p. 25 (sine descrip t ione). 



3) Notes Leyden Mus., v. 12, 1890, p. 83. 



4) Proc. Acad. Nat. Sc. Philadelphia, 1S58, p. 99. Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 103, pi. 13, f. 4. See also 

 Ortmann, ziool. Tahrb., Syst., Bd 7, 1894, p. 748. It must be noted, however, that Zehntner (Rev. suisse zool., t. 2, 1894, p. 177, 

 pi. 8, f. 21 — 22) maintains the distinctness of M. brevidactyhis, but his arguments seem to me to be of little importance. The "Siboga" 

 specimens at least could, by a mixture of characters, be referred as well to either of the two species. 



5) In the Australian Bush, Engl. transl., London, 1899, p. 491. The observation was made during the writer's stay at Amboyna. 



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