^5 

 I. Vanina /itterata (Fabricius). 



Literature and description: Alcock, Journ. As. Soc. Bengal, v. 69, prt 2, p. 401. 



Stat. 4. Djangkar, north-east coast of Java. 7 cT- ' 9- 



Stat. 19. Labuan Tring, west coast of Lombok. 3 c? juv. 



Stat. 33. Bay of Pidjot, east coast of I.ombok. 2 cf juv. 



Stat. 50. Labuan Badjo, west coast of Flores. 2 cf juv, 



Stat. 58. Seba, Savu Island, west of Timor. 7 cf (i 'id-, 6 juv.). 



Stat. 234. Nusa Laut, east of Ambon, i Q juv. 



This well known species is found everywhere throughout the Indo-Pacific region, and, as 

 Alcock remarks, it ascends estuaries even into freshwater, though also commonly met with at 

 sea on floating timber. The "Siboga" specimens were all caught in rivers. 



The terminal segment of the abdomen of the very young cf is about as long as broad, 

 not of the elongate shape that is observed in the adult. 



Ptychognathus Stimpson. 



1858. Ptychognathus Stimpson. Proc. Ac. Nat. Sc. Pliiladelphia, 185S, p. 104. 

 1868. Gnathograpsus A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 4, p. 180. 

 1880. Coelochirns Nauck. Zeitschr. wiss. Zoo!., Bd 34, p. 66. 



De Man ^) has been the first to recognize the identity of Ptychognathus and GnatJio- 

 grapstis aiid the same author has stated "), that Coelochirtcs has been founded likewise on a 

 species of the present genus. 



The genus contains a rather great number of species, some of which have a perfectly 

 horizontal and straight front, resembling that of Varima, while in others it is obliquely deflexed. 

 Now Miss Rathbun ^) recently proposes to include those species with a Varima-Yik.^ front, with 

 the epibranchial teeth acute and well separated, and the wrist of the chelipeds armed at the 

 inner angle with a tooth, into the genus ]'ariina. I have preferred, however, to maintain 

 Ptychognathus in its original conception, according to which the genus is characterized by the 

 broad exognath, that is at least as broad as, generally, especially in the cf, much broader then, 

 the ischium of the external maxillipeds, whereas in Vai'iina the exognath is much narrower 

 than the ischium. Besides, in Varuna the exognath is thin, lamellar and hairy at the outer 

 surface, in both sexes, but in the cT of Ptychognathus it is convex, thick and wholly glabrous. 



The discrimination of the species is rendered difficult by the rather considerable differences 



between the two sexes of the same species. The best key to all the Indo-Pacific species is 



that recently given by de Man *), for cf and Q separately. After the publication of his key no 



less than 4 new specimens have been described by Miss Rathbun (one of these referred to 



Varuna) viz.: 



i) Notes Leiden Mus., v. 5, 1883, p. i6i. 



2) Zool. Jahrb., Syst., Bd 2, 18S7, p. 719. 



3) Proc. U.S. Nat. Mus., v. 47, 1914, p. 69. 



4) Proc. Zool. Soc. London, 1905, p. 543 — 544. 



8s 



