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6. Rhynchoplax inachoides (Alcock). 



1900. Hymenicus inachoides Alcock. Journ. As. Soc. Bengal, v. 69, prt 2, p. 388. 

 1902. Hymenicus inachoides Alcock. 111. Zool. "Investigator", Crust. prt 10, pi. 65, f. 1. 



Hab. Port Canning' (near Calcutta). 



7. R/iynchop/ax coralicola Rathbun. 



1909. Rhynchoplax coralicola Rathbun. Proc. Biol. Soc. Washington, v. 22, p. 108. 



1910. Rhynchoplax coralicola Rathbun. K. Dansk. Vid. Selsk. Skr., 7. Raekke, Afd. 5, n° 4, 



p. 316, f. 5. 



Hab. Singapore. 



Elamena H. Milne-Edwards. 



1837. Elamena H. Milne-Edwards. Hist. nat. Crust., t. 2, p. 33. 

 1S53. Elamene": H. Milne-Edwards. Ann. Sc. Nat., (3) t. 20, p. 223. 



The French author included in his genus only one species, E. mathaei (Desmarest), but 

 in 1853 he seems to have mistaken a c? of Halicarcinus planatus (Fabricius) for the former 

 species 1 ), besides including at the same time two species in the genus, that are very imperfectly 

 known, but apparently not to be placed here. So there is some confusion about the right inter- 

 pretation of Milne-Edwards' diagnosis, but we must consider his first description of 1S37 

 reliable. According to this account Elamena is characterized by the much flattened and lamellar 

 carapace, by the broad, triangular rostrum, beneath which the antennules and the antennae are 

 hidden ; the antennules are separated by a vertical septum ") ; the orbits are scarcely indicated ; 

 the epistome is distinct and long; the merus of the external maxillipeds is quadrate, cut obliquely 

 anteriorly and shorter than the ischium. A good diagnosis of the genus is provided by Alcock 3 ). 

 Usually, if not always, the distal end of the mero- and carpopodite of the walking legs is 

 produced upward. 



In the following I have attempted to distinguish between the species 4 ) of the genus: 



1 . Front trilobate, the lobules of about equal length and obtuse, 



widely separated 2 



Front shortly triangular or truncate 3 



2. Palm of cheliped much swollen, apparently as long as fingers. 



Median lobe of rostrum placed below the level of the lateral 



lobes. Corneae of eyes visible from above E. minuta A. Milne-Edwards 



Palm of cheliped not much swollen, longer than fingers. Lobes 

 of rostrum not horizontal, but pointing obliquely upward. 



1) See Haswell, Cat. Austral. Crust., 1S82, p. 114, and Stebuing, Proc. Zool. Soc. London, 1900, p. 520 — 521. 



2) This character seems to be wanting in some species. 



3) Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 385. 



4) I have excluded the following species: E. quoyi H. Milne-Edwards (Ann. Sc. Nat. (3) t. 20, 1853, p. 223, pi. II, f. 3) 

 which, as noted above, is likely to be identical with Hymenicus fubescens Dana; E. mexicana II. Milne-Edwards (Ibid, p. 224), charact- 

 erized in a few words by the author and not only doubtful by its imperfect diagnosis but also by its pretended habitat (coast of Mexico): 

 and finally E. lacuslris Chilton, which in my opiuion is a Hymenicus (*ee p. 12). 



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