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Genus Costacallista Palmer.
1926. Pal. Amer., vol. 1, no. 5, pp. 73, 84.
Type (by orginal designation): Venus erycina Linné, Recent, Indo-Pacific.
Figured: Palmer, op. cit., Pl. 15, figs. 17, 18, 21.
Costacallista hectori (Finlay and Marwick). Plate 10, figs. 13, 15.
1937. Notocallista hectori Fin. and Marw., N.Z. Geol. Surv. Pal. Bull., 15, p. 101, pl. 14, figs. 11, 12, 16.
When described, this species was compared with the Parisian Eocene Tivelina elegans (Lamk.) and T. baudoni Cossman. These, together with T. elegantula (Desh.) and distans (Desh.), can well be classed as Costacallista, and hectori, having similar sculpture, may be included. Certainly the broad, concentric ridges of hectori separate it from any of the groups of Notocallista yet known.
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Typical Tivelina (G.-type, Cytherea tellinaria Lamk.) is sub-triangular with a smaller pallial sinus and without strong sculpture. Jukes-Brown (1913, p. 342) has pointed out that Cossmann's Tivelina of the Iconographie Complète contains several different groups, among which he used Callista for baudoni, elegans and elegantula. The species heberti (Desh.) from the Cotentin Eocene is also strongly ridged and, like the other species mentioned, appears to differ from the type of Costacallista only in its small size.