obsolete fine concentric folds, also irregular growth furrows, on young shell are fine regular concentric ridges. Left valve with narrow anterior cardinal joined above to broader, triangular, bevelled median; posterior cardinal fairly long, reaching almost to hinge-margin separated from nymph by very narrow groove and slightly diverging at its lower end, anterior lateral fairly long and strong, diverging from near the top of the anterior cardinal, left valve with rather narrow, grooved posterior cardinal, paired median and anterior cardinals and deep anterior pit with laterals. Pallial sinus fairly deep, broadly rounded at the end, directed at the upper part of the anterior adductor, valve margins smooth.

Paradione differs from Macrocallista in so many ways that it should be generically separated. The left anterior cardinal of Macrocallista nimbosa Solander is fairly strong, triangular and grooved, the median is very little broader and rugose and the posterior one is extremely narrow and is joined to the nymph without an intervening groove, also the two front teeth slope strongly backwards. In the right valve the posterior cardinal is very narrow and does not nearly reach the hinge-margin, both the median and anterior teeth are directed backwards. The typical Macrocallista further differs from Paradione greatly in size and shape, the pallial sinus is truncated at the end and horizontal, and the pedal retractor is well separated from the anterior adductor.

Iredale (1924, p. 210) in rightly banishing Macrocallista from Autralian usage was not correct, however, in stating that this generic name was given to an American fossil. By monotypy Macrocallista Meek (1876, p. 179) is based on Venus gigantea Gmelin = V. nimbosa Solander.

Subgenus Notocallista Iredale, 1924.

Type: Cytherea kingi Gray.

Notocallista differs only in minor details from Paradione ovalina. The shells of both groups are of the same size and shape, the hinge-teeth are almost identical and the pallial sinus in the earlier species is the same. In sculpture there is no great difference. The recent P. multistriata has generally fine, regular concentric ridges, but in many of the specimens from Castlecliff and the Middle Tertiary the ridges are obsolete over a large part of the disc. The young P. ovalina of 1 cm. length has practically the same sculpture as the adult P. parki. P. ovalina differs from any of the southern species in being more polished, in having irregularly-placed growth furrows and in the pedal retractor being joined to the anterior adductor.

Paradione (Notocallista) multistriata (Sowerby) (Figs. 70, 71, 72).

1851 Cytherea (Callista) multistriata Sow., Thes. Conch., vol. 2, p. 628, pl. 136, fig. 177.

1873 Callista disrupta Desh., Hutton, Cat. Tert. Moll., p. 21 (not of Desh.).

1893 Cytherea assimilis Hutton, Macleay Mem. Vol., p. 81, pl. 9, fig. 89 a, b. (not of Hutton, 1873).

For further synonymy see Suter's Manual, p. 982.

The shape of this shell is somewhat variable and it is possible that more than one species is represented, but a good series of recent examples is lacking. The original type is a somewhat gibbous shell with high beaks. E. A. Smith in the Challenger Report figured and described a flat, oval variety, but did not propose a separate name. In the Castlecliff beds, both of these types and many other variations in shape are represented. The flat form was often called Macrocallista assimilis by Suter, but the type of that species has a crenulated margin and is related to Tawera spissa (Quoy and Gaimard).

Localities: Recent (type); Landguard Bluff, Wanganui; Castlecliff; Ngaruroro River; Hawera Beach.

Paradione (Notocallista) parki n. sp. (Figs. 66–69).

Shell rather small, sub-oval, moderately inflated; beaks about anterior third, prominent. Lunule long, sagittate, striated; escutcheon not definitely marked except by a weakening of the sculpture. Sculpture of very fine, close, concentric riblets often obsolete on centre of disc where shell has shining appearance. Hinge-plate long; right valve with anterior and median cardinals of equal strength and semilunar, their inner margins parallel and vertical; posterior cardinal a little longer, but narrow and grooved unequally; anterior laterals parallel to lunular margins. Left valve with anterior cardinal lamellar, almost vertical, joined above to median which is fairly strong, triangular, and bevelled; posterior cardinal short, lamellar, confluent with nymph; anterior lateral fairly long, high, pointed; nymphs slender. Pallial sinus moderate, rounded in front, ascending, directed at anterior adductor or above it.

Holotype (a right valve) in collection of N.Z. Geological Survey.

Height 15.5 mm., length 20 mm., thickness (one valve) 5 mm.

Localities: Parson's Creek, Oamaru, type [J. Park, 1916 (= M. multistriata of Suter, 1921, p. 80)]; Awamoa; Target Gully (= M. assimilis and M. multistriata of Suter, 1921, p. 83); greensand, Wharekuri; Chatton Creek.

This shell, which is not uncommon in the glauconitic sands at the Shell Bed, Target Gully, has always appeared in previous lists as Macrocallista multistriata or M. assimilis. There are, however, between the Miocene and Recent shells constant differences which warrant specific distinction. In P. parki, characteristically a smaller shell, the beaks are more prominent, the posterior is regularly convex and not acuminate, and the pallial sinus is always rounded in front, whereas in P. multistriata it is truncate. In P. parki the right anterior cardinal is equal in strength to the median, not weaker than it, while the left posterior is sometimes longer than in the recent shell.

Paradione (Notocallista) trigonalis n. sp. (Fig. 73).

Shell small, subtrigonal, plump; beaks high, about anterior third or less, posterior narrowly rounded. Lunule large, lanceolate, little impressed, bounded by shallow line; escutcheon broad, very shallow,