although it was not possible to expose satisfactorily the invaginate peristome.

Horizon and Locality.—Te Whanga Series; north end of Red Bluff, six miles north of Waitangi, Chatham Island.

Description.—The approximate dimensions of the test in mm. are:—

Ambital outline oval, pointed posteriorly. Adapical surface flattened in the region of the apical disc; highest point excentric posteriorly. Ambitus rounded. Adoral surface depressed round peristome. Peristome ? oval, elongated transversely, excentric anteriorly, deeply invaginate. Periproct oval to subtriangular, elongated transversely, below ambitus. Apical disc excentric anteriorly; plating-structure not preserved.

It has not been possible to expose the floscelle to permit complete description; but the bourrelets are inconspicuous, and the arrangement of the pores is shown in text-figures 4, 8 and 9.

Since the details of the petals given above are inferred rather than observed, it is necessary to discuss in detail the facts on which they are based. In petals I, II and V, the sutures are visible, either in the test or in the secondary calcite, everywhere except near the apical disc, where the two or three plates in each column near the oculars are obscure. The numbering of the plates as given in text-figures 5–7 may therefore be slightly inaccurate. In petal Ib, Plate 39 contains two pores, close together; in Plate 41 there are definitely no large pores. Plate 40 is obscure, but is narrower than plates 39 and 41; it is taken as the end of the petal. Plates 34 and 35 are also narrow; this may be correlated with the curvature of the petal. The corresponding narrow plates in Va (in the petaloid region of which the test has been removed leaving the secondary calcite) are plates 36 and 44; the latter is taken (by analogy with Ib) as the end of the petal. Traces of pores are seen in plates 39 to 43 inclusive.

In Ia, traces of the inner pores are seen in the secondary calcite corresponding to plates 28, 29 and 30; there are no petaloid pores in Plate 39 (and onwards to the ambitus) although the test is present. Plates 31–37 are all narrow, but they are also higher than Plate 30. In the corresponding column, Vb, Plate 36 is the narrowest plate, and Plate 37 is higher.

In IIa, the test is preserved in the region of the end of the petal; Plate 39 contains two large pores; Plate 40 is relatively higher and obscure. In IIb, the test is preserved from Plate 34 to the ambitus

and shows no sign of petaloid pores; the narrowest plate appears to be 25, but the adradial suture is obscure, and there is little variation in height of the plates in this region.

If, therefore, we may assume that the end of the petaloid portions of each column are marked by an increase in width and height of the plates, the figures given in the table above are substantially correct; and the petals of Ib and Va contain about ten pore-pairs more than do Ia and Vb, while IIa is markedly longer than IIb. The curvature of the petals is shown in text-figures 5–7.

Text-figures 5–7; petals.
Fig. 5.—Ambulacrum I; tubercles indicated by circles × 20/3.
Fig. 6.—Ambulacrum II. × 10/3.
Fig. 7.—Ambulacrum V; in the stippled area the test is missing, exposing limestone matrix × 10/3.

The ornamentation is typical of Echinolampas: the median region of the unpaired interambulacrum, from near the peristome halfway to the periproct, is granular, without primary tubercles (near the periproct, the surface of the test is missing).

Comparison with other Australasian species.

Echinolampas ovulum Laube (1869, Über einige fossile Echiniden von den Murray Cliffs in Süd-Australien: Sitz. Ber. k. Akad. Wiss. Wien, Math.-naturw. Classe, Bd. 59, Abth. 1, pp. 191–2), as redescribed by Duncan (1887, A Revision of the Echinoidea from the Australian Tertiaries: Quart. Journ. Geol. Soc. London, vol. 43, p. 420) and by Gregory (1890, Some Additions to the Australian Tertiary Echinoi-

dea: Geol. Mag., p. 483, pl. 13, figs. 7, 8), is easily distinguished by, for instance, its smaller peristome and the petals, the pore-fields of which are equal in length in the petals of the posterior paired ambulacra. According to Tenison-Woods (1878, Palacontological Evidence of Australian Tertiary Formations: Journ. Proc. Roy. Soc. New South Wales, 1877, vol. 11, pp. 116, 125) and Tate [1885, Notes on… the Basin of the Lower Murray River: Trans. Roy. Soc. S. Australia, vol. 7 (for 1883–4), p. 37], E. ovulum Laube is a synonym of E. gambierensis Tenison-Woods [The Teriary Rocks of South Australia, part 4, Fossil Echinidae: Trans. Adelaide Phil. Soc. (1864–5), figs. 1a–c].^*

Eclinolampas morgani Cotteau (1890, Echinides nouveaux oupeu connus, 9e article: Mem. Soc. Zool. France, Tome 3, pp. 546–7, pl. 12, figs. 13–15) from the “Eocene” of Mount Gambier, Australia, is less depressed, the apical disc is not so excentric anteriorly, and the disparity between the two pore-fields of each petal is not so marked.

Conoclypeus rostratus Tate [1894, Unrecorded Genera of the Older Tertiary Fauna of Australia…: Journ. Proc. Roy. Soc. New South Wales, vol. 27 (1893), pp. 194–5, pl. 13, figs. 1, a, b], later placed in the genus Plesiolampas by Tate (1898, A Second Supplement to a Census of the Fauna of the Older Tertiary of Australia: Journ. Proc. Roy. Soc. New South Wales for 1897, vol. 31, p. 411), was renamed Progonolampas tatei by Lambert (1924, Lambert et

Text-figures 8–9; arrangement of pore in the phyllodes.
Fig. 8.—Ambulacrum III.
Fig. 9.—Ambulacrum IV.
Near the margin of the peristome (shaded in the figures), the test is invaginate; the distances between the adoral pores as shown in the figures is therefore considerably foreshortened.

Thiéry, Essai de Nomenclature Raisonnée des Echinides, fasc. 6 and 7, p. 387), who regards Progonolampas Bittner as a subgenus of Echinolampas. The species is easily distinguished by its tumid bourrelets and long petals.

Progonolampas novae-hollandiae Bittner (1892, Über Echiniden des Tertiärs von Australien: Sitz. Ber. k. Akad. Wiss. Wien, Math.-naturw. Classe, Bd. 101, Abth. 1, pp. 357–9, tab. 3, fig. 1) is closely similar, but differs in its greater relative height, its oval ambital outline, and in the much lower number of pore-pairs in the petals, which are, however, of similar dimensions. Bittner distinguished his genus Progonolampas from Echinolampas by the pores of the petals; in Progonolampas the pores are neither elongate nor conjugate. Whether the pores of the Chatham Island specimen are conjugate or not cannot be determined, owing to the state of preservation; but the outer pore of Plate 39 in column Ib (where the test is preserved) is circular.

E. posterocrassus Gregory (1890, op. cit., pp. 483–4, pl. 13, figs. 4–6) agrees closely in its shape, excentricity of apical disc, and shape and relative dimensions of the periproct. Examination of the holotype in the British Museum (Natural History), registered E 3381, shows that the adoral margin of the periproct is rounded (not angular, as figured by Gregory), and that the outer pores of the petals are slightly elongated. The number of pore-pairs in each column of petal I is about the same as in the Chatham Island specimen: but according to Gregory, the “porc-pairs of the anterior pair of petals are slightly unequal.”

Echinolampas corioensis McCoy (1874, in R. Brough Smith, Report of Progress, Geol. Surv. Victoria, p. 36; Miocene) seems to be a nomen nudum: (R. Etheridge, 1875, Description of a new species… from Tertiary Rocks of Victoria, Australia…; Quart. Journ. Geol. Soc., London, vol. 31, p. 449).

Discussion of horizon.—Although the descriptions of the type specimens of P. novae-hollandiae Bittner and E. posterocrassus Gregory show considerable differences, Tate (1892, Critical Remarks on A. Bittner's “Echiniden des Tertiärs von Australien”: Trans. Roy. Soc. South Australia, vol. 15, part 2, p. 193), who collected the material described by Bittner, is emphatic that the type specimens of P. novae-hollandiae are “authentic examples of Gregory's species” E. posterocrassus. Since the Chatham Island specimen agrees with E. posterocrassus in those features in which it differs from P. novae-hollandiae, and agrees with P. novae-hollandiae in those features in which it differs from E. posterocrassus, it could be identified as E. posterocrassus Gregory as understood by Tate.

There is considerable difference of opinion as to the age of E. posterocrassus. Dennant and Kitson, for instance (1903, Catalogue of the Described Species… in the Cainozoic Fauna of Victoria, South Australia and Tasmania: Records Geol. Surv. Victoria, vol. 1, part 2, p. 131) regard it as Eocene. Chapman, on the other hand (1915, Report on a Collection of Fossils made by Dr. A. Wade from the Cainozoic Series of South Australia, appendix 2 in A. Wade, Geol. Surv. South Australia, Bull. No. 4, p. 47) records the species from the Miocene, and states that it is “confined to Janjukian Strata.” Chapman's view is here preferred, since the evidence for the Miocene age of the Janjuian (as defined by Chapman) is based on the larger foraminifera, which probably afford the best criteria for the correla-