26: 



853- Naranio costata Gray, Ann. Mag. Nat. Hist., (2) XI, p. 38. 



853. Naranio divaricata Deshayes, Cat. Conch. Brit. Mus., I, Veneridae etc., p. 216. 



853. Petricola lapicida Morch, Cat. Yoldi, II, p. 20. 



854. Petricola divaricata Sowerby, Thés. Conch., II, p. TJ^-, pi- CLXVI, figs. 24, 25. 

 857. Choristodon divaricatum Adams, H. & A., Gen. Rec. Moll., II, p. 442, pi. CX, figs. 2, 2a 

 866. Petricola divaricata Mabille & Le Mesle, Journ. Conchyliol., XIV, p. 117. 

 869. Petricola divaricata von Martens, von Deckens Reise, III, p. 66, pi. III, figs. 3, la, b. 

 874. Petricola divaricata Sowerby in Reeve, Conch. Icon., XIX, Petricola, pi. III, fig. 22. 



877. Petricola lapicida Pagenstecher, Zool. Ergebn. Reise, Rothenmeer Mollusk., p. 41. 



878. Choristodon divaricatum (ex parte), Kobelt, Illustr. Conchylienbuch, p. 340, pi. XCIX, 

 fig. 18. 



880. Petricola lapicida (nec Gmelin), von Martens, Môbius Beitràge Meeresf. Mauritius, 



Seychell., p. 327. 

 884. Petricola lapicida (nec Gmelin), Smith, Rept. Voy. "Alert", p. 98. 



884. Petricola lapicida (nec Gmelin), Grasset, Ind. Test. Viv., p. 260. 



885. Petricola lapicida (nec Gmelin), Smith, "Challenger" Lamellibranchia, p. i!3. 



890. Choristodon lapicidinii Paetel, Cat. Conch. Samm., III, p. 96. 



891. Naranio divaricata Fischer, P., Bull. Soc. Hist. Nat. d'Autun, IV, p. 235. 

 899. Naranio lapicida (nec Gmelin) Hedley, Mem. Austral. Mus., III, pp. 502, 529. 

 902. Choristodon lapicidnm (nec Gmelin) Shopland, Proc. Malacol. Soc. London, V, p. 178. 



902. Petricola lapicida Smith, (nec Gmelin), Faun. Geogr. Maldive, Laccadive Archipel., II, 

 p. 626. 



903. Choristodon lapicidiiim (nec Gmelin) Pritchard & Gatliff, Proc. Roy. Soc. Victoria, XVI, 

 p. 121. 



906. Choristodon lapicidimn (nec Gmelin) Melvill & Standen, Proc. Zool. Soc. London, p. 837. 

 906. Petricola lapicida (nec Gmelin) Hedley, Proc. Linn. Soc. N. S. Wales, XXXI, p. 466. 



909. Naranio lapicida (nec Gmelin) Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat. Math., 

 (7) V, p. 253. 



910. Petricola lapicida (nec Gmelin) Hedley, Austral. Ass. Adv. Sci., XII, p. 349. 

 912. Petricola lapicida (nec Gmelin) Verco, Tra'ns. Roy. Soc. Soc. Australia, XXXVI, i, 



p. 205. 



916. Petricola lapicida (nec Gmelin) Hedley, Journ. Proc. Roy. Soc. VV. Australia, I, p. 166. 



917. Naranio lapicida (nec Gmelin) Odhner, Kungl. Svensk. Akad. Handl., LU, N" 16, p. 27. 

 921. Naranio liicmalis Lamy, Bull. Mus. d'Hist. Nat. Paris, XXVII, p. 433. 

 923. Petricola [Naranio) lapicida (nec Gmelin) Lamy, Journ. Conchyliol., LXVII, p. 337. 



Most authors hâve followed Smith in uniting the West Indian Petricola {Choristodon) 

 lapicida (Gmelin) with the Indo-Pacific P. (C) divergens. After a careful scrutiny of the literature 

 on the two species and the available collections, I am of opinion that Smith's suggestion regarding 

 the two species being synonymous, cannot be accepted as correct. The shells of the tv^^o species, 

 owing to their living in dead coral blocks vary along similar lines, but the sculpture of the two 

 species, as was pointed out by Chemnitz as early as 1788, is quite différent. In P.{C.) lapicida 

 the shells do not hâve the fine zigzag sculpture so well developed as is found on shells of ail 

 âges of the East Indian species P. {C.) lapicida. The raised oblique ridges which run from the 

 umbones to the posterior slopes are, as Smith pointed out, présent or absent in varying degrees 

 on shells of différent ages; thèse are in any case not structural parts of the shells, but are due 

 to a déposition of extraneous calcareous matter. 



Distribution: P. {C.) divergens is widely distributed in the Red Sea, the Indian Océan, 

 Persian Gulf and in the Australian waters. 



The "Siboga" Expédition collected two shells at the Anchorage off Labuan Pandan, 

 Lombok (St. 34). 



SrBOGA-EXPEDlTIE XXXIIIl^. 



34 



