215 



In gênerai I find that the conclusions of Dautzenberg and Fischer are fully borne out 

 by my work. I, however, ag-ree with Tomlin in regarding thèse differently coloured forms as 

 colour phases rather than as distinct varieties of M. lueretrix. 



In the "Siboga" collection the only type represented is the phase castanea (Lam.). Thèse 

 shells are of a uniform brownish grey or chestnut colour with the slightly convex post-dorsal 

 area, with the vulva (of Hornell) of a darker shade than the rest of the shell ; the area, 

 however, is not so dark or marked off as in the forma typica. 



Distribution : — M. meretrix has a wide range in the Indo-Pacific Région. A detailed 

 list of the records of the species was published by Oostingh. 



In the "Siboga" collection the species is represented by two young shells collected in 

 the Bay of Pidjot, Lombok (St. 33).- 



Genus Macrocallista Meek. 



1876. Macrocallista Meek, Palaeontol. Upper Missouri, p. 179. 



1902. Macrocallista Dali, Proc. U. S. Nat. Mus., XXVI, p. 351. 



1903. Macrocallista Dali, Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 125 1. 



191 3. Callista Jukes-Browne, Proc. Malacol. Soc. London, X, p. 344. 



1914. Callista Jukes-Browne, Proc. Malacol. Soc. London, XI, p. 60. 

 1924. Notocallista Iredale, Proc. Linn. Soc. N. S. Wales, XLIX, p. 210. 



I agrée with Dall that the generic name Callista of Poli having been used by Leach 

 for Venus verrucosa Linn. cannot be accepted for the species for which it was later adopted 

 by MoRCH, Gray, Romer and other authors. The next available name is Macrocallista Meek, 

 with Macrocallista nimbosa (Solander) as the génotype. Iredale's new generic name Notocallista 

 is an absolute synonym of Macrocallista. 



I. Macrocallista phasianella (Deshayes). 



1853. Diane phasianella Deshayes, Proc. Zool. Soc. London, p. 2. 

 1853. Diane phasianella Deshayes, Cat. Conch. Brit. Mus., I, Veneridae etc., p. 64. 

 1857. Callista phasianella Adams, Gen. Rec. MolL, II, p. 426. 

 1863. Dione phasianella Reeve, Conch. Icon., XIV, Diane, pi. XII, fig. 56. 

 1867. Venus [Cytherea, Callista) pJiasianella Romer, Mon. Venus, I, p. 62. 

 1884. Cytherea phasianella Grasset, Ind. Test. Viv., p. 265. 

 i8go. Callista pJiasianella Paetel, Cat. Conch. Samm., III, p. 70. 

 1903. Callista flarida (ex parte). Hidalgo, Obras Malacol., II, p. 195. 

 1906. Callista phasianella Standen & Leicester, Ceylon Pearl Oyster Rept., V, p. 293. 

 1906. Callista phasianella Melvill & Standen, Proc. Zool. Soc. London, p. 830. 

 191 1. Venus [Callista) phasia^iella Pelseneer, "Siboga" Lamellibranches (Anat.), pp. 52, 53, 

 pi. XIX, fig. 10. 



In the above synonymy I hâve not included Rômer's figures of the species on pi. XVII 

 (figs. 4, \a, ô) as they do not agrée in outline or sculpture with shells of this species. 



M. phasianella has a rather oblongate-ovate, sometimes trigonal and solid shell, with 

 somewhat prominent and forwardly inclined umbones. The sculpture consists of rather flat 

 concentric, broad hand-like ridges separated by only superficial linear grooves. The sculpture is 

 better developed on the anterior half of the valves, and in most young shells the posterior half 



