(h) Pliocene.

The Lower Pliocene is marked in New Zealand chiefly by the disappearance of Miocene lines, presumably due to a cooling climate, and no particular introductions are known until the Castlecliffian. Even at Castlecliff the only strikingly new additions occur well up in the series. The large Pectinid Notovola (Finlay, 1930, p. 51), the Indo-Pacific Eunaticina (Powell, 1934, pp. 268, 269), and Leucotina A.Ad. (s.str.) are all marked new-comers, conspicuous in the Pliocene of Japan, and all of very short life here, except Notovola, which is still common. The Glycimerid group Glycimerula Finlay and Marwick (1937, p. 23), which is also characteristic of the Japanese Pliocene and Recent, reached New Zealand somewhat earlier, probably at the beginning of the Pliocene. Even later immigrations have occurred, perhaps in the Pleistocene, in the form of Anadara trapezia L. (Powell, 1932, p. 70) and some Cymatiidae (Finlay, 1926B, p. 398, etc.; Powell, 1933, pp. 156–159), and are still occurring at the present time; e.g., Gadinia conica Angas, Hydatina physis (Linné), Recluzia lutea (Bennett) (Powell, 1924, p. 282), Polinices simiae (Desh.) (Powell, 1934, p. 156).