41 



lo. Arca [Anadard) birleyana Melvill. 



1907. Arca {Scapharca) birleyana Melvill in Melvill & Standen, Proc. Zool. Soc. London, 

 p. 794, pi. LUI, fig. 8. 



I refer a few spécimens froni the localities enumerated below to this species vi^ith some 

 doubt. Ail thèse spécimens are stray valves of young spécimens, not exceeding 9 mm. in length. 

 The outline and the sculpture consisting of large numbers of close-set radial ribs is similar to 

 that of the type, but the ribs are not uniform and in young shells appear somewhat denticulated. 



Distribution: — The spécimens which I refer to this species were collected by the "Siboga" 

 Expédition in the Bay of Bima (St. 47), Bay of Nangamessi, Sumba (St. 53), West of Kvi' andang 

 Bay Entrance (St. 116), and at St. 306 (8°27'S., 122° 54^.5 E.). 



Subo-enus Barbatia Gr 



'<=> 



ay. 



1844. Barbatia Gray, Synop. Brit. Mus., p. 81. 



1847. Barbatia Gray, Proc. Zool. Soc. London, p. 198. 

 1857. Barbatia Adams, H. & A., Gen. Rec. Moll., II, p. 534. 



1898. Barbatia Dali, (ex parte), Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 614. 



1907. Barbatia Lamy, Journ. ConchylioL, LV, p. 3. 



1927. Barbatia Cox (ex parte), Rept. Palaeontol. Zanzibar, p. 94. 



Though Gray did not characterize Barbatia in the first two publications cited above, 

 and the -first description of it was not published till 1858, there can be no doubt about its 

 limits. The type of the subgenus is A. [B.) barbatia Linn. 



Good définitions of Barbatia are given by Adams, Dall and Lamy, and it is only 

 necessary to indicate hère that I regard Acar Gray as a distinct subgenus of equal rank to 

 Barbatia. 



I. Arca {^Barbatia) cometa Reeve. 



1844. Arca cometa Reeve, Conch. Icon., II, Arca, pi. XVI, fig. iii. 



1844. Arca cometa Reeve, Proc. Zool. Soc. London, p. 127. 



1845. Arca cometa Catlow & Reeve, Conch. Nomencl., p. 48. 



1848. Arca cometa Nyst, Mém. Acad. Roy. Belgique, XXII, p. 18. 



1857. Arca [Barbatia) cometa Adams, H. & A., Gen. Rec. Moll., II, p. 534. 



1860. Arca cometa Reeve, Elem. Conch., II, p. 93. 



1890. Barbatia cometa Paetel, Cat. Conch. Samm., III, p. 212. 



1891. Arca [Acar) cometa Kobelt in Martini Chemn. Conch. -Cab. (N. F.), VIII (2), Arca,^. 190, 



pi. XLVI, fig. 7. 

 1896. Barbatia cometa Casto de Elera, Cat. Sist. Filip., p. 802. 

 1905. Arca Cometa Hidalgo, Cat. Filip., p. 371. 



1907. Arca [Barbatia) cometa Lamy, Journ. ConchylioL, LV, p. jÇ). 



191 1. Arca [Barbatia) cometa Pelseneer, "Siboga" Lamellibranches (Anat.), p. 14, pi. II, fig. 3. 

 1929. Arca [Barbatia) cometa Dautzenberg, Faun. Colon. Français., III, p. 575. 



I agrée with Lamy that Arca cometa should be placed in the subgenus Barbatia and 

 not Acar, as Kobelt had done. Lamy pointed out the distinctive features of the species but the 

 following notes on the type of the species in the British Muséum (Nat. fiist.), London, should 

 prove useful. The species is small in size, having an elongated shell with a very short anterior 



SIBOGA-EXPEDITIE LUI C. 6 



