6i 



placed almost below the ligament and separated by a short edentulous space from 4 — 5 more 

 horizontal teeth of the posterior séries ; muscle scars hardly visible ; inner ridge of anterior margin 

 with very minute, irregular ribs; thèse are almost absent on the posterior margin and the shell 

 margin in this area appears almost smooth. 



Measurements (in millimètres) 



Length 6.3 6.2 



Height 7.4 7.3 



Diameter 2 (left valve) 2.2 (right valve). 



Habitat: — 4 stray valves of this interesting species were dredged at St. 90 (1° 17^.5 N., 

 ii8°53'E.) at a depth of 281 mètres. 



Remarks : — L. dazitzenbergi is allied to L. obliqtia A. Adams ^) from Japan, but is 

 distinguished by its shape, sculpture and the altogether différent hinge. 



Genus Glycymeris Da Costa. 



1778. Glycymeris'-) Da Costa, Brit. Conch., p. 168. 



1799. Pectunciihcs Lamarck, Mém. Soc. Hist. Nat. Paris, p. ^y. 



1898. Glycymeris Dali, Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 607. 



1904. Pectunciihis Dautzenberg & Dollfus, Journ. Conchyliol., LU, pp. 109 — 122. 



1905. Glycymeris Dali, Journ. Conch., XI, pp. 145, 146. 



19 12. PecUinculus Lamy, Journ. Conchyliol., LIX, pp. 81 — 84. 



1925. Glycymeris Woodring, Miocène Mollusks from Bowden, Jamaica, Pelecypods, etc., p. 24. 



1927. Glycymeris Cox, Rept. Palaeontol. Zanzibar, p. 65. 



1930. Glycymeris Stewart, Spécial Publication Acad. Nat. Sci. Philadelphia, N". 3, p. 70. 



Dautzenberg and Dollfus hâve discussed their reasons for adopting the generic name 

 Pectu7iculus in préférence to Glycymeris. They accept Huddersford ^) as the author of the genus 

 rather than Lamarck, but in Huddersford's work the word Pectunculi is used as a vernacular 

 name and not in a generic sensé, as it is understood today. I hâve, therefore, following Dall, 

 Woodring, Cox and Stewart aHopted Glycymeris Da Costa in préférence to PechmctUus 

 Huddersford. 



Glycymeris orbicularis Da Costa is accepted, by tautonomy, as the génotype of Glycymeris., 

 but this species, as Bucquoy, Dautzenberg and Dollfus *) hâve shown, is synonymous with 

 G. glycymeris (Linn.). 



I. Glycymeris amboinensis (Gmelin). 



1709. Concha indica etc., Bonanni, Mus. Kircher, p. 448, pi. XVII, fig. 129. 



1742. Concha crassa, striata Gualtier, Ind. Test. Conch., pi. LXXII, fig. li. 



1771. Knorr, Vergnùgen der Augen, etc., V, pi. XII, fig. 4. 



1784. Arca pectunculus Chemnitz (ex parte), Conch. Cab., VII, pi. LVIII, figs. 568, 569. 



1790. Cardium amboinense Gmelin, Syst. Nat. (éd. XIII), p. 3255. 



1792. Schwarzgefleckte GogelJiôpflein Bruguière, Encyclopéd. Méthod., p. 20, pi. CCCXI, fig. 5. 



1827. Pectiincidus pectiniformis Blain ville, Man. MalacoL, pi. LXV, fig. 3. 



i) Adams, A. — Proc. Zool. Soc. London, p. 229 (1862). 



2) Spelt as Glycimeris in Index p. il (1778). 



3) Huddersford, G. — Martini Lister's Hist. Conch. Index, p. 6 (1770). 



4) Bucquoy, E., Dautzenberg, P. and Dollfus, G. F. — Moll. Roiissilon, II, pp. 195 — 199, pi. XXXIV (1891). 



