The time-honoured designation Leiolophus has been substituted by Perenon l ) in recent times. 

 Key to the species : 

 i. Large species, with a tutt of hairs at inner surface of 



palm of chela /'. pilimanum (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 . planissimum (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. abbreviatwm (Dana) 



1. Perenon planissimum (Herbst). 



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



Stat. ■$$. Bay of Pidjot, east coast of Lombok. 1 $ juv. 



Stat. 34. Labuan Pandan, west coast of Lombok. 5 rf aet - div., 2 9 with eggs. 



Stat. 47. Bay of Bima, Sumbawa. 1 Q. 



Stat. 58. Savu, between Timor and Sumba. S <ƒ (1 juv.), 7 9 (5 with eggs). 



Stat. 125. Siau Island, north-east of Manado. 1 9 w ' tn e gg s - 



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



Stat. 129. Karkaralong Islands, between Mindanao and Celel^es. 1 c?> L 9- 



Stat. 131. Karakelang, Talaut Islands. 5 9 ( one witli Sacculind). 



Stat. 169. Atjatuning, west coast of New Guinea. 2 rf. 



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

 Grapstts strigosus (Herbst) the most common species of the Grapsidae. 



2. Perenon abbreviatum Dana. 



185 1. Accmthopus 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. 1 1. 

 187S. Leiolophus abbreviatus Miers. Ann. Mag. Nat. Hist. (5.) v. 1, p. 154. 



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

 1888. Leiolophus abbreviatus de Man. Arch. Naturgesch., Jahrg. 53. 1., p. 372. 

 1892. 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) Rathbun, Proc. U.S. Nat. Mus., v. 22, igoo, p. 281. 



2) Plagusia planissima} Randall, Journ. Ac. Nat. Sc. Philadelphia, 1839, p. 128 (f. Rathbun, 1906); Acanthopus pilimanus 

 A. Milne-Edwards, Nouv. Arch. Mus. Paris, t. 9, 1S73, p. 300, pi. 14, f. 5; Leiolophus p. Miers, Ann. Mag. Nat. Hist. (5) v. I, 1878, 

 p. 154: Kingsley, Proc. Ac. Nat. Sc. Philadelphia, 1880, p. 224; Ortmann, Zool. Jahrb., Syst., Bd 7, 1894, p. 731; Perenon pilimanus 

 Rathbun, Buil. U.S. Fish Comm. for 1903, v. 23, prt 3, 1906, p. S42. Hab. New Caledonia, Tahiti, Fiji and Hawaiian Islands. 



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

 of "Acanthopus affinis" and "A. tcnuifrons", both described by H. Milne-Edwards (Ann. Sc. Nat. (3) t. 20, 1853, p. 180), these specimens 

 should also enter into the synonymy of the present species. 



r 3° 



