I30 

 Tlie time-honoured designation Leiolophus has been substituted by Percnon 'j in recent times. 

 Key to the species : 



1. Larcje species, with a tuft of hairs at inner surface of 



palm of chela P. pilimamun (A. Milne-Edw.) ') 



Smaller species, with the cnelae hairless 2 



2. Anterior margin of epistome with one large median tooth 



and two smaller lateral ones; pleural groove, limiting 

 the pterygostomial region dorsally, hairy. Abdomen 

 of cf broad, terminal segment triangular. Upper border 



of chelae entire P- planissiiiuim ( Herbst) 



Anterior margin of epistome only with one large median 

 tooth, the lateral ones wanting; pleural groove hairless 

 or nearly so. Abdomen of cf narrow, terminal segment 

 roughly semi-circular. Upper border of chelae sulcate P. abhrcviatuin (Dana) 



1 . Percnon planissimum (Herbst). 



Literature: Alcock, Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 439^). 



Stat. ■^^i. Bay of Pidjot, east coast of Lombok. i cT j"^'- 



Stat. 34. Labuan Pandan, west coast of Lombok. 5 cf aet. div., 2 Q ^^'tli eggs. 



Stat. 47. Bay of Bima, Sumbawa. i 9- 



Stat. 58. Savu, between Timor and Sumba. 8 cf (i juv.), 7 9 (5 ^^'ith eggs). 



Stat. 125. Siau Island, north-east of Manado. i 9 "''th eggs. 



Stat. 127. Great Sangir Island. 2 cf juv. 



Stat. 129. Karkaralong Islands, between Mindanao and Celebes, i cf' ' 9- 



Stat.' 131. Karakelang, Talaut Islands. 5 O (one with Sacculina). 



Stat. 169. Atjatuning, west coast of New Guinea. 2 cf- 



This species has a world-wide distribution throughout the warmer seas, and is with 

 Grapsus strigosns (Herbst) the most common species of the Grapsidae. 



2. Percno7i abbreviaUun Dana. 



1851. Acanthopus abbreviatus Dana. Proc. Acad. Nat. Sc. Philadelphia, 185 1, p. 252. 



1852. Acanthopus abbreviatus Dana. U.S. Expl. Exp., Crust., p. 373, pi. 23, fig. 11. 

 1878. Leiolophus abbreviatus Miers. Ann. Mag. Nat. Hist. (5) v. i, p. 154. 



1880. Leiolophus abbreviatus Miers. Ann. Mag. Nat. Hist. (5) v. 5, p. 314. 



1888. Leiolophus abbreviatus de Man. Arch. Naturgesch., Jahrg. 53. i., p. 372. 



1S92. Leiolophus abbreviatus Thallwitz. Abhandl. Mus. Dresden, Bd 3, n" 3, pag. 36. 



1894. Leiolophus. abbreviatus Ortmann. Denkschr. med.-naturw. Ges. Jena, Bd 8, p. 57. 



1) KatiiI'.u.n, Pioc. U.S. Nat. Mus., v. 22, 1900, p. 281. 



2) P!a«usia ptanissinia} Randall, Jouin. Ac. Nat. Sc. Philadelphia, 1S39, p. 12S (f. K.mhbun, 1906): Acanthopus piUmaiius 

 A. Milne-Edwards, Noiiv. Arch. Mus. Paris, t. 9, 1873, p. 300, pi. 14, f. 5; Leiolophus p. Miers, Ann. Mag. Nat. Hist. (5) v. i, 1878, 

 p. 154; KiNdSLEY, Proc. Ac. Nat. Sc. Philadelphia, 1880, p. 224; Ortmann, ZooI. Jahrb., Syst., Bd 7, 1894, p. 731; rcrcnon pilimanus 

 Rathbun, Bull. U.S. Fish Coram, for 1903, v. 23, pvt 3, 1906, p. 842. Hab. New Caledonia, Tahiti, Fiji an4 Hawaiian Islands. ^ 



3) According to Dli Man (Abhandl. Senckenb. Gesellsch., Bd 25. Heft 3, 1902, p. 544), who examined the original specimens 

 of '^Acani/iopiis affinii' and "-4. icnuifrons'\ both described by H. Milne-Edwards (Ann. Sc. Nat. (3) t. 20, 1853, p. 180), these specimens 



•Iso enter into the synonymy of the present species. 



