isS 



^0 



Miss Rathbun 1), however, maintains Heteroplax as a distinct genus and records both of 

 Stimpson's species from the Gulf of Siam, but without any comment whatever. 



As to Platvozius it was first estabhshed by Borradaile as a subgenus of Pseudozms\ 

 afterwards =) it was declared to be nearer related to Pihivinoplax, but still regarded as belonging 

 to the Xanthidae. Though it must be admitted that the limit between Goneplacidae and Xanthidae 

 is largely arbitrary, the position of the male organs in such genera as Pilumnoplax, Eiicrate 

 etc. certainlv points to the Goneplacidae, and I have associated Platyozins with Ejicrate, on 

 account of its general appearance, notwithstanding Borradaile's not mentioning anything about 



the antennae. 



Five species in all are here included in the genus ■'), one of which has been dredged 



by the "Siboga". 



Key to the species : 



1. Margins of carapace without teeth or at most with two incon- 



spicuous nodules. Chelipeds in cf very massive, longer than 



the walkino- leo^s E- haii!ilio7ii Mc Culloch*) 



Antero-lateral margins of carapace four-toothed 2 



2. Front transversely grooved. Antero-lateral teeth of carapace all 



distinct, but the two middle ones on each side the largest . 3 

 Second and fourth antero-lateral teeth nearly obsolete ... 4 



3. Large species (breadth of carapace 30 — 40 mm.); carapace 



much convex longitudinally, not sculptured, only with an 



oblique ridge on posterior teeth E. crenata (de Haan) '') 



Small species (breadth of carapace 15 — 20 mm.); carapace more 

 flattened, with some short transverse ridges anteriorly; on the 

 branchial regions at each side a more or less distinct, longi- 

 tudinal ridge, laterally of which the carapace is strongly 

 declivous E. sitlcatifrons (Stimpson) 



4. Length of carapace to breadth as i : 1.27 E. dentata (Stimpson)") 



Length of carapace to breadth as i : i .46 E. transversa (Stimpson) ") 



I. Eiicrate siilcati fronts (Stimpson). 



1858. Filumnoplax siilcatifrons Stimpson. Proc. Ac. Nat. Sc. Philadelphia, 1858, p. 93. 

 1877. Piiitmnoplax sulcatifrons Targioni-Tozzetti. Viag. "Magenta", Crost., p. 102, pi. 7, f. 2. 



j) K. Dansk. Vid. Selsk. Ski., 7. Raekke, Afd. 5, n" 4, 1910, p. 342. 



2) L. c, p. 429. 



3) The species E. se.xdentata HaswcU, mentiond by Alcock (1. c, p. 301), in veality belongs to the Piioriopladnac 

 {Homoiopla.x Rathbun). 



4) Rec. Austval. Mus., v. 7, 1908, p. 58, pi. 12, f. i. Hab. Queensland. 



5) Cancer (Eticrate) crenatus de Haan, Faun. Japon., Crust., 1835, p. 51, pi. 15, f. i; Emrate crenata Urtmann, Zool. Jahrb., 

 Syst., Bd 7, 1894, p. 688; Rathbun, Proc. U.S. Nat. Mus., v. 26, 1903, p. 23. Hab. Japan. 



6) Htleroplax dentata Stimpson, Proc. Ac. Nat. Sc. Philadelphia, 185S, p. 94; Rathbun, K. Dansk. Vid. Selsk. Skr., 7. Raekke, 

 Afd. 5, n" 4, 1910, p. 342; Stimpson, Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 94. Hab. Hongkong and Gulf of Siam. 



7) Heteroplax transversa Stimpson, Proc. Ac. Nat. Sc. Philadelphia, 1S58, p. 94; Rathbun, K. Dansk. Vid. Selsk. Skr., 7. 

 Raekke, Afd. 5, n» 4, 1910, p. 342; Stimpson, Smithson. Inst., Miscell. Coll., v. 49, 1907, p. 95. Hab. Hongkong and Gulf of Siam. 



