(2) Minus varices other than outer lip.

There is a tendency rarely shown in certain individuals of Euspinacassis and Xenophalium to leave undissolved the variced outer lip preparatory to making another growth stage (Fig. 35). This is probably a recessive character traceable to an ancestral type, normally leaving the varix at each growth stage as in Recent typical Phalium.

Species observed exhibiting this feature are:—

Euspinacassis pollens Finlay (holotype).

Xenophalium insperatum (Iredale) 2 Mount Maunganui, N.Z.

X. pyrum (Lam.) 5 Recent N.Z. and 1 Castlecliff (Up. Pliocene) N.Z.

X. labiatum (Perry) 1 Broken Bay, New South Wales, Australia.

Dentition: The radulae of the following species were mounted for study:—

X. pyrum (Lam.).

2. Mount Maunganui, Bay of Plenty.

1. Off Kapiti Island in 25 fath.

1. Off Cuvier Island in 40 fath.

X. hamiltoni nov.

1. Off Cape Campbell in 35–40 fath.

X. insperatum (Iredale).

2. Mount Maunganui, Bay of Plenty.

X. labiatum (Perry).

1. Shell harbour, New South Wales, Australia.

X. labiatum X inseperatum (Iredale).

1. Mount Maunganui, Bay of Plenty.

The radula (Fig. 1) is situated behind a pair of jaws (Fig. 2) contained in a long proboscis (Fig. 3 pr.) and is composed of numerous rows of transparent chitinous teeth arranged on a long

transparent ribbon, fitted on either side at the front end with lobes by which it is fixed in position, the rear portion being free. The dimensions of the entire radula in X. hamiltoni are 5.8 mm. in length by 0.85 mm. in width, and on it are arranged 102 rows of 7 transverse teeth, making 714 separate teeth, which are also furnished with separate cutting points or cusps to the number of 3,366.

Text Figures.
Fig. 1.—Entire radula showing lobes by which it is attached (Xenophalium hamiltoni).
Fig. 2.—Jaws and plates, greatly magnified (X. hamiltoni).
Fig. 3.—External features of animal (X. pyrum) about natural size. E, eyes; F, foot; L, liver; M, mantle; OP, operculum; P, penis; PR, proboscis; R. radula; S, siphon; T, tentacles.
Fig. 4.—Three transverse rows from radula of X. hamiltoni. Second and third pair of marginals on left not drawn in.
Fig. 5.—Central tooth from radula of X. hamiltoni.
Fig. 6.—A lateral tooth from radula of X. hamiltoni.
Fig. 7.—Pair of marginals from radula of X. hamiltoni (from above).
Fig. 8.—Lower marginal from radula of X. hamiltoni (from below).
Fig. 9.—Pair of marginals from radula of X. insperatum (from above).
Fig. 10.—Lower marginal from radula of X. labiatum (from below).

These two extremes are almost bridged by a puzzling series of Miocene and Lower Pliocene shells having prominent nodulous sculpture similar to that of Euspinacassis but with a ridged columella as in typical Xenophalium. Closer comparison, however, shows that while Euspinacassis has secondary sculpture in the form of dense spiral striae continuous over the nodules, the Miocene-Pliocene series have the secondary sculpture confined to the spaces between the spiral series of nodules.

The grangei-fibratum series are better placed in Xenophalium on account of the great similarity in the form of the columella. Taking the Tertiary species here ascribed to Xenophalium in their geological sequence we find a gradual reduction in the number of nodulous rows from five in toreuma to one in fibratum.

In Xenophalium and Casmaria the fasciole usually lacks the longitudinal striae whose presence is quite a constant feature in Phalium, Semicassis, and Euspinacassis. However, as the fasciole of Xenophalium is not invariably smooth, no importance can be attached to the presence or absence of this feature in the genus.

There seems no doubt that Xenophalium is the evolutionary product of Euspinacassis but they are best considered as distinct genera having at least one differentiating character in the form of the columella.

If we admit evolution of species then evolution of genera must also apply. The fact that Euspinacassis is extinct and Xenophalium now the ruling Australasian Recent Cassid supports this contention.

Xenophalium kaawaense Powell & Bartrum. (Fig. 32.)

1928 Trans. N.Z. Inst., vol. 59, p. 145, Figs. 53 and 54.

Type. Kaawa Creek. (Lower Pliocene).

Xenophalium fibratum (Marshall & Murdoch).

1920 Trans. N.Z. Inst., vol. 52, p. 131, Pl. 8, Figs. 16 and 17.

Type. Waipipi, Taranaki. (Lower Pliocene).

Xenophalium wanganuiense n. sp. (Fig. 36.)

Shell moderately large, ovate, rather thin. Spire and base sculptured with conspicuous linear grooves. A series of indistinct nodules on shoulder of last whorl. Suture rapidly descending on last half-whorl. Columellar callus-plate thick enclosing very small false umbilicus. Outer lip rather thin, rounded, recurved and smooth within.

Height, 64 mm.; diameter, 48 mm.

Holotype and 1 paratype in collection of N.Z. Geological Survey.

Habitat: Wanganui (Upper Pliocene), Castlecliff (type) 2 sp. N.Z. Geol. Surv.; 2 sp. A. W. B. P., Jan. 1927; Kai Iwi. Fragment A. W. B. P., Jan. 1927. Apparently a descendant of the Lower Pliocene X. fibratum.

Xenophalium pyrum (Lamarck). (Figs. 20, 21 and 22.)

The type has been localized by Iredale as coming from Southern Tasmania (1927, p. 339). Shells referrable to pyrum are also found Recent in shallow water from New South Wales and New Zealand and fossil from the Upper Pliocene of Wanganui, New Zealand. Although no hard and fast differences separate Tasmanian from New Zealand specimens, most of the former have a heavy columellar plate showing a small umbilical cavity, while the predominant New Zealand type has a thin plate directed forwards showing a considerably larger cavity. Even these features however are by no means constant.

It is evident by the occasional occurrence in New Zealand, of the common Australian cassids, labiatum and insperatum, and the Kermadee Island royana, herein recorded, that an effective means of dispersal exists, no doubt by means of pelagic larvae. Divergence between the Tasmanian, New South Wales, and New Zealand colonies of pyrum would otherwise be expected but for the assumed fairly regular interchange of larvae by the agency of ocean currents.

The only fossil example I have seen of true pyrum is here figured (Fig. 22). It was collected by Mr. W. La Roche recently at Castlecliff, Wanganui, Upper Pliocene, and measures 69 mm. X 52 mm. All other Cassids I have examined from the Wanganui beds have been referrable to either X. wanganuiense n. sp., X. harrisonae n. sp. or Semicassis multisecta (Finlay).

The following New Zealand localities for typical pyrum are known to the writer.

Mount Maunganui and Opotiki, Bay of Plenty (common). 40 fathoms off Cuvier Island (Fig. 21). Motutara, West Coast (dead shells inhabited by hermit crabs), Paraparaumu and Waikanae Beaches, Cook Strait. (Dominion Museum.) 25 fathoms off Kapiti Island, Cook Strait. (Dominion Museum). Castelcliff, Wanganui. Upper Pliocene. (W. La Roche, 1927).

A large thin-shelled form of pyrum, with shoulder-nodules and basal spirals obsolete, occurs in deep water around the New Zealand coasts. It cannot be regarded as the normal benthal variant of the shallow water species, as typical pyrum also occurs in corresponding depths. It is convenient therefore to regard this form as a subspecies of pyrum.

Xenophalium pyrum powelli (Finlay).^* (Figs. 23 and 24.)

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Shell large, thin, globose. Spire low 1/7 height of shell. Outer lip thin, expanded and recurved, smooth within. Whorls 7½, plus small, globose protoconch of 2½ smooth whorls. Upper spire-whorls finely spirally striated, crossed by faint axial costae. Body-whorl smooth except for indistinct axial growth-lines and very faint indications of basal spirals. Columellar-callus thin, inclined forward, leaving a wide false umbilicus. Colour uniformly pinkish-fawn with irregular axial patches of reddish-brown radiating from suture. Five or six irregular blotches of purplish-brown on outer lip, indicating

the termination of faint colour-bands, only visible on latter part of body-whorl.

Height, 79 mm.; diameter, 66.5 mm. (Specimen in author's collection, Auckland.)

Habitat: Vicinity of Cuvier Island, Bay of Plenty in about 40 fathoms. From local trawler about 1920. Off Eastern Coast of Great Barrier Island in deep water. Mount Maunganui (Ocean Beach) (Dr. C. E. R. Bucknill) and Opotiki (Mr. W. La Roche) cast up alive after gales. Waikanae Beach, Cook Strait (A.W.B.P., 20/12/1927). 40–50 fathoms off Cape Campbell, Marlborough. (Dominion Museum, H. Hamilton, July 1925).

Xenophalium hamiltoni n. sp. (Figs. 25 and 26.)

Shell large, solid, globose, spire low. Spire and base striated and with several deeper grooves immediately below suture. Entire absence of nodules. Whorls 7½, plus small, globose protoconch of 2½ whorls. Columellar-callus thick, inclined forward, leaving a moderately open false umbilicus. Outer lip thin, expanded, recurved, and smooth within. Colour uniformly pinkish-fawn or light-brown with no traces of colour pattern. Interior of aperture, outer lip, columella and parietal callus whitish. Occasional specimens have a few irregular reddish-brown blotches on outer lip.

Height, 71 mm.; diameter, 55 mm. (holotype). (Fig. 26.)

Height, 86.5 mm.; diameter, 66 mm. (largest paratype).

Holotype and 12 paratypes in Dominion Museum, Wellington.

Habitat: Off Cape Campbell, Marlborough, in about 60 fathoms. Collected by Mr. H. Hamilton from S.T. “Futurist,” July 1925.

Xenophalium ericanum n. sp. (Fig. 29.)

Shell very large and solid, minus nodules, base smooth. Spire less than ⅓ height of shell. Whorls 7½, including small, globose protoconch of 2½ smooth whorls. First two post-nuclear whorls finely reticulated by flat-topped spiral riblets and slightly retractive narrow axial threads. There are about 14 spirals, the upper four smaller, more closely spaced and marked off from the others by a shallow sub-sutural depression. In the holotype the later whorls are almost smooth except for irregular growth-lines and a few faint spiral threads below suture. In the paratype these growth-lines are much more prominent, particularly above the periphery. Aperture large, ovate. Outer lip strong, thickened, and slightly recurved, with about 23 strong denticles along inner margin. Columellar-callus thick, curving forwards forming an open false umbilicus. Pillar with seven, short strong plications and the usual ridges bordering the base of columellar-callus. Fasciole sculptured with irregular longitudinal striae. Colour pinkish-fawn, mottled with small irregular reddish-brown patches, arranged in obscure spiral series becoming more definite towards outer lip. Five bands on body-whorl.

Height, 108.5 mm.; diameter, 62.5 mm. (holtype).

Height 98.5 mm.; diameter, 62 mm. (paratype).

Holotype in author's collection; paratype in collection of Mrs. F. W. Sanderson, Whangaroa.