The genus Heloecius Dana 1 ) being not represented in the "Siboga" collection, we may 

 pass directly to Ocypoda. 



Ocypoda Fabricius. 

 1798. Ocypoda Fabricius. Suppl. Entom. Syst., p. 347. 



The members of this genus frequent sandy beaches, where they inhabit long burrows 

 near high-water mark, into which they dart back when alarmed. The speed with which they 

 dash to their burrows or to the sea is remarkable and has been especially noticed by the 

 earliest pre-Linnean authors. The majority of the species is in the possession of a stridulating 

 ridge, at the inner surface of the palm of the larger cheliped ; this ridge is rubbed against 

 a longitudinal rim on the ischiopodite of this cheliped, and so a squeaking sound is produced. 

 On the habits of Ocypoda and the use of the stridulating ridge Alcock a ) has published an 

 interesting account. 



An attempt to review the species has been made in earlier years by Kingsley s ) and 

 by Miers 4 ), but better by Ortmann 3 ). After the last revision only a few new species have 

 been described, viz. : 

 O. iiobilii de Man. Abhandl. Senckenb. Gesellsch., Bd 25, Heft 3, 1902, p. 478, pi. 19, f. 2—3, 



from the Baram river (Borneo) 6 ). 

 O. jousseaumei Nobili. Buil. Mus. d'Hist. Nat., 1905, n" 4, p. 233, f. 2, and: Ann. Sc. Nat. (9) 



t. 4, 1906, p. 310, from the Red Sea. 



and a new subspecies : 



O. rotundata Miers subsp. arabica Nobili. Buil. Sc. France et Belgique, t. 40, 1906, p. 152, 



pi. 5, f. 26, from the Persian Gulf. 



Besides, Miss Rathbun remarks 7 ), after examination of Dana's original specimen of 

 O. laevis, that this species has always been wrongly considered identical with O. cordïmana 

 Desmarest, but the difference between the two species is not indicated. 



The "Siboga" collected only three widely-distributed species. 



1. Ocypoda cordïmana Desmarest. 



Literature: Ortmann, Zool. Jahrb., Syst., Bd 10, 1897, p. 362 and Alcock, 1. c. p. 349. 



Stat. 40. Pulu Kawassang, Paternoster Islands. 1 9- 

 Stat. 50. Labuan Badjo, west coast of Flores. 1 cj. 

 Stat. 179. Kawa Bay, west coast of Ceram. 1 9- 



1) For synonymy and literature see Hasweix, Cat. Austral. Crust., 1882, p. 91. Cf. also de Man, Zool. Jahrb. Syst.. Bd 2, 

 1887, p. 696. 



2) Ann. Mag. Nat. Hist. (6) v. 10, 1892, p. 336. 



3) Proc. Acad. Nat. Sc. Philadelphia, 1880, p. 179. 



4) Ann. Mag. Nat. Hist. (5) v. 10, 1882, p. 378. 



5) Zool. Jahrb., Syst., Bd 7, 1894, p. 761 and ibid., Bd 10, 1897, p. 359. 



6) The author discusses at the same time the characteristic features of O. stimpsoni Ortmann (= O. convexa Stimpson nee 

 Quoy et Gaimard). 



7) Buil. U.S. Fish Comm. for 1903, v. 23, prt 3, 1906, p. 834, pi. 7, f. 2. 



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