49 



11. Arca [Barôatia) wendti Lamy. (Plate I, figs, 60, 61). 



1874. Barbatia Wendtii Dunker, Cat. Mus. Godeffroy, V, p. 173. 



1877. Barbatia Wendtii Dunker, Cat. Mus. Godefifroy, VI, p. 96. 



1890. Barbatia {Acar} Wendti Paetel, Cat. Conch. Samm., III, p. 214. 



1907. Arca Wendti Lamy, Journ. Conchyliol., LV, p. 45, pi. i, figs. 11 — 13. 



1909. Arca wendti Hedley, Proc. Linn. Soc. N. S. Wales, XXXIV, p. 423. 



19 10. Arca ivettdti Hedley, Austral. Ass. Adv. Sci.. XII, p. 344. 



Neither Schmeltz nor Dunker ever published any description of the species A. [B.) wendti 

 and the name was a no m en nudum till Lamy referred some shells from the Island of EHza- 

 beth (?) and from New Caledonia to it, and pubhshed a detailed description and figures of it. 

 Lamy included the species in the subgenus Arca s.s. with some doubt. Later Hedley recorded 

 this species from the Australian waters. In the "Siboga" collection there are a number of shells 

 from the localities enumerated below, and which agrée with a shell named A. wendti by 

 Hedley and now in the collections of the British Muséum (Nat. Hist.), London. I am further 

 of opinion that it is a true Barbatia. I publish photographs of a shell of the species. 



Distribution: — The "Siboga" shells of this species were obtained off Labuan Pandan, 

 Lombok (St. 34) and on the Bornéo Bank (St. 80). 



12. Arca [Barôatia) zueôeri sp. nov. (Plate I, figs. 62, 63). 



The following is a description of this new species, which I associate with the name of 

 Prof. Max Weber, the leader and guiding light of the "Siboga" Expédition: — 



Shell médium sized, elongated, subtrapezoidal, somewhat compressed, thin ; dorsal and 

 ventral margins subparallel ; anterior margin sub-rounded ; posterior margin truncated above, 

 acutely extended below ; umbos relatively low, broad, lying at about anterior third of length ; 

 posterior ridge distinct, but not very prominent ; région behind ridge somewhat excavated with 

 two well-marked radial ridges ; radial sculpture consisting of 27 — 28 narrow, low, regular ribs, 

 some of the ribs are grooved and a few interspaces bear narrower secondary ribs, more parti- 

 cularly near the margin ; interspaces very narrow, thread-like ; concentric sculpture consisting of 

 very thin, not very deep growth lines and furrows which eut up the radial ridges into circular 

 to ovoidal beak-like areas ; sculpture better marked on left than on right valve; cardinal area 

 moderately narrow, bearing transverse striations ; inner margin of valves particularly along 

 anterior and posterior régions fluted. 



Length 18.8 mm.: height 9.4mm.: diameter 5.6mm.: length of hinge 10.4mm. 



Holotype : A complète shell dredged from a depth of 32 mètres, lY^ miles south of 

 Tandjong Lajar, South coast of Bawean Island (St. 322). 



Remarks: — A. (B.) weberi is distinguished by its shape and very peculiar sculpture. 

 In gênerai form it resembles A. {B.) cometa Reeve, but the sculpture is less prominent, though 

 much more regular : the shell valves are also much thinner. 



Subgenus Acar Gray. 



1857. Acar Gray, Ann. Mag. Nat. Hist., (2) XIX, p. 369. 



1857. Acar Adams, H. & A., Gen. Rec. MolL, II, p. 535. 



1907. Acar Lamy, Journ. Conchyliol., LV. p. 3. 



1927. Acar Cox, Rept, Palaeontol. Zanzibar, p. 94. 



SIBOGA-EXPEUITIE LIII<r. 7 



