Localities:—

• Holotype, Recent.

• 206—Shakespeare Cliff, Wanganui.

• Castlecliff, Wanganui (Marshall).

• Waihi, near Hawera (Marshall and Murdoch).

• 749 (in part) — Mouth of Ruarnahanga River, Palliser Bay.

• (Fragment.)

• 81—Castle Point. (Shell slightly more globose, ribs more regular.)

• 231—McLean's, Ngaruroro, River, Hawke's Bay. (An old, heavy shell, with beak and ribs like the Castle Point shells.)

• Tokomaru (Marshall). (A very worn specimen, but similar to those from Castle Point.)

• ? 649—Paparoa Rapids, Wanganui River. (One imperfect specimen.)

• ? 786—Mount Donald, Weka Pass. (An imperfect specimen, more inflated than usual: Pal. Bull. No. 8, p. 42, last list.) This specimen resembles that from loc. 231.

• ? 246—Cape Rodney, Auckland. (A distorted specimen.)

The locality-numbers are those of the New Zealand Geological Survey (see N.Z. Geol. Surv. Pal. Bull. No. 1).

It will be noted that positive identification could not be made in the last three localities. The shells are undoubtedly of this group, but may represent different species.

McCoy (1875, p. 26, pi. xix, figs. 9–13) has described and figured specimens attributed to this species from the “Lower Tertiary ” of Bird Rock, Geelong; Mount Eliza and Mount Martha, at Schnapper Point. With reference to this, Tate (1885, p. 137) says, “The identification of the fossil and the living species has been disputed by Mr. R. M. Johnston. The material at my command is not sufficient to permit me to express an opinion, though I have little hesitation in accepting Professor McCoy's determination in respect to the fossil represented by fig. 10.”,

Unfortunately, no material from Australia was available for this paper, and opinions based upon figures and descriptions are not so reliable as those based on the actual specimens. However, the excellent figures of the Prodromus show no difference between the anterior and posterior ribbing, so the specific identity of the two shells is open to doubt.

Records to be eliminated from N.Z. Geol. Surv. Pal. Bull. No. 8:—

• Page 25. Manaia Beach. These shells belong to the huttoni group, and are here placed as a new species = G. manaiaensis.

• Page 30. Lower Awatere, loc. 126 = G. manaiaensis.

• Page 31. Starborough Creek = G. manaiaensis.

• Page 40. Moonlight Creek = G. manaiaensis.

• Page 44. Motunau beds, Weka Pass = G. manaiaensis.

• Page 45. Motunau beds, Weka Pass = G. manaiaensis.

• Page 45. Motunau beds, Weka Pass = G. manaiaensis.

• Page 45. Motunau beds, Lower Waipara = G. manaiaensis.

• Page 46. Motunau beds, Mid-Waipara = G. manaiaensis.

• Page 53. Kakahu = G. subglobosa (distorted).

• Page 57. Pareora, loc. 458 = G. huttoni (worn).

• Page 59. White Rock River, loc. 165 = G. huttoni (worn).

• Page 85. Bed K, tuffs south of Cape Wanbrow = Venericardia sp. (common in this locality).

In the cases cited above, as well as in the rest of this paper, the specimens have actually been handled. In the case of many other occurrences noted by Suter the specimens are missing from the Geological Survey collections; in fact, no undoubted specimen of G. laticostata has been seen from strata older than Wanganwan.

Cardium brachytonum Suter.

N.Z. Geol. Surv. Pal. Bull. No. 5, p. 17; pi. x, fig. 5, 1917.

The holotype on examination proves to be the cast of a Glycymeris, probably laticostata. In the plate reproduced in Bulletin No. 5 the extremities of the hinge-area have been blocked out by a black background.

Glycymeris traversi (Hutton). (Plate M, fig. 8.)

1873. Pectunculus traversi Hutton, Cat. Tert. Moll., p. 28.

1914. Glycymeris traversi (Hutton): Suter, N.Z. Geol. Surv. Pal. Bull. No. 2, p. 35, pl. iv, figs. 2a, 2b.

In his description Suter gives the locality of the lectotype as Chatham Islands. The actual specimen in the Dominion Museum is labelled “ Loe.? ” However, the shell is almost certainly from Chatham, so Suter's statement may stand.

Buchanan's drawing of this shell, reproduced by Suter (see above), does not represent accurately the wide interstices between the ribs. From the drawing one would take the shell to be inseparable from G. laticostata; this, however, is not so. The interstices are equal in width to the ribs, even at the margin of a 2J in. shell; thus the ribs in G. traversi are noticeably narrower than in G. laticostata. As to Suter's statement that the former is less inflated than the latter, the present examination does not bear out the observation. The inflation is practically the same in shells of equal size. There is very little difference in width between the anterior and posterior ribs.

The shell from loc. 786, Mount Donald, in this paper provisionally placed under G. laticostata, may be the same as the one from Weka Pass placed under G. traversi by Hutton (1873, p. 28). If so, Hutton's record of this species from that locality must be deleted, as the specimen in question has broadly rounded ribs, and so is nearer G. laticostata. No specimen of G. traversi from New Zealand rocks has been seen during this examination, nor can I find a record of its having been identified by Suter.

Glycymeris lornensis n. sp. (Plate 1, figs. 4, 9.)

Shell, medium-sized, suborbicular. to longitudinally oval, equilateral: beaks only moderately raised above the- dorsal margin, which is short, anterior end convex, the dorsal margin sloping; posterior end similar; sculpture consisting of 25 to 30 rounded, radiating ribs which reach the margin but become obscured in some specimens by strong growth-lines, the interstices rounded and narrower than the ribs; margins weakly crenate; hinge-plate deeply encroached on by the ligamental area, even in small individuals, leaving three or four teeth on each side; ligamental area relatively large, steeply inclined, and very closely grooved by about 12 well-incised lines.

Holotype in collection of N.Z. Geological Survey.

Height, 40 mm.; length, 40 mm.; thickness, 14 mm. (one valve).

• (g.) Kawau: No specimens very near the type were seen.

• (h.) Oamaru: The many fossiliferous localities in this district and the various horizons represented give Hutton's use of the name a very wide meaning. The Target Gully “ shell-bed ” was unknown to him, and, as he used “ Awamoa ” as a separate locality, it is hard to say from where his specimens came.

Thus it will be seen that there is room for considerable doubt as to the exact limits assignable to this species. The shells from the upper beds at Broken River, though more oblique than the Kanieri one, have the same strong anal sinus. Specimens similar to the Broken River ones are common at White Rock River, Pareora, and these, principally, were used in this paper for comparative purposes (see Plate 7, fig. 2).

Localities:—

• Kanieri. (Lectotype.)

• 165—White Rock River, Pareora. (Also a flat variety in Otago Museum collection.)

• 458—Lower Gorge, Pareora River.

• 237—“ Upper part of Mount Brown limestone, Trelissick.”

• 451a—Pareora beds, Thomas and Porter Rivers.

• Lower Gorge, Waipara (Marshall). (Shells more oblique and with sloping shoulders; perhaps a new species.)

• Muddy Terrace, Waikaia (Marshall).

• Opihi River, South Canterbury (north bank, two miles west of Pleasant Point) (Marwick).

• Grey Marls, Mead Gorge, 25 ft. below conglomerate (Thomson).

• Tutamore Ridge, Poverty Bay district (Ongley and Macpherson).

• Shingly Creek, Lake Heron (Canterbury Museum collection; two specimens, one with a high, sharp beak).

• Records to be eliminated from N.Z. Geol. Surv. Pal. Bull. No. 8:—

• Page 23. Onairo = G. manaiaensts.

• Page 45. Motunau beds, Weka Pass = G. manaiaensis.

• Page 48. Trelissick Basin, loc. 239 = G. trelissickensis.

• Page 49. Trelissick Basin, loc. 449 = G. trelissickensis.

Glycymeris subglobosa Suter. (Plate 3, fig. 3; Plate 4, fig. 3.)

1917. Glycymeris subglobosa Suter, N.Z. Geol. Surv. Pal. Bull. No. 5, p. 66, pl. vii, fig. 8.

For the description of this species Suter used, in addition to the Kakahti material from which he chose his holotype, a paratype from Target Gully. This latter shell belongs to a different species (G. robusta n. sp.), and has been responsible for such features as “ more inflated than globosa” and “ secondary ornamentation on the ribs ” in Suter's description.

The number of ribs on the holotype is 56, but other specimens have as few as 48. This species is distinguishable from G. hutioni by its somewhat rounded ribs and interstices. In this feature (seen only in well-preserved samples) it resembles the Cretaceous species—an interesting fact when its low stratigraphical position in the Tertiary is remembered. The angle of the beak is wider than that of G. huttoni, the anal depression is not so marked, and the outlineas more nearly equilateral.

Localities:—

164—Kakahu. (Holotype.) (Also in Dr. Marshall's collection.)

176—Black Point. (Poor specimens.)

Although this shell has been recorded from many horizons—as high, indeed, as Wanganuian—these determinations must be considered extremely doubtful. No specimens examined from other than the two localities given above can be .placed in this species.

Glycymeris robusta n. sp. (Plate 3, fig. 5; Plate 4, fig. 5.)

Shell very large, heavy, much inflated, subquadrate; beaks very prominent; anterior dorsal margin long, curved, descending gradually; anterior end bluntly angled above; posterior dorsal margin shorter, more rapidly descending; posterior margin with a flattened curve; basal margin meeting the posterior in a blunt angle, but curving regularly to meet the anterior; anal depression moderate; sculpture consisting of about 43 ribs, broad on the anterior and middle part of the disc, but narrow on the posterior; interstices narrow, but widening slightly towards the margin; crenulations of the inner margin obsolete posteriorly; ligamental area long and fairly wide, with four well-spaced ligamental grooves; teeth long and strong, horizontal at the extremities of the hinge-line; anterior muscular impression large, triangular; posterior smaller, subquadrate.

Dimensions of holotype (right valve): Height, 74 mm.; length, 75 mm.; thickness, 30 mm.

Localities:—

• Target Gully (Park, 1916). (Holotype, in collection of N.Z. Geological Survey.) Specimens collected also by Marshall, Benson, and Finlay.)

• 649—Paparoa Rapids. (Collected also by Marshall and Murdoch.)

• 1017—Raekohua Valley, Tangarakau. (Specimen of 108 mm. height.)

• Mead Gorge gravels (1 from conglomerate). Collected by Dr. Thomson. This specimen was (apparently accidentally) in the Geological Survey locality collection from Awatere Valley, loc. 126, and was accompanied by a label of Suter's, “Cucullaea alta.” This record must therefore be deleted from Pal. Bull. No. 8, p. 30.

• ? Orari River. (Canterbury Museum collection, fragmentary specimen.)

• Point Hill, Glenavy. (Otago University collection.)

• ? 166—Lower Gorge, Pareora. (A poor specimen, flatter than usual; listed by Suter in Pal. Bull. No. 8, p. 57, as G. subglobosa.)

• 483—McKay's “ Hutchinson's Quarry greensands,” Wharekuri. (A fragment.)

Remarks.—The holotype was used by Suter as a paratype for his G. subglobos a from Elakahu. The excellence of its preservation makes one wonder why he did not make it the holotype of his species, instead of the matrix-filled specimen that he used. Perhaps he doubted the exact specific identity of the Target Gully and the ELakahu shells.

Although a large shell, the holotype is not quite full-grown, and so does not present all the characteristics of the old individuals, which are as much as 108 mm. in height. These are thicker and heavier, the shoulders are more rounded, while the area is broad and has encroached on the teeth, which are thick and irregular. The flattened posterior margin is extended ventrally, making the shell more inequilateral.

This species is larger and more tumid than G. subglobosa; the ribs, too, are wider. Young shells of G. robusta would be very like mature G. subglobosa, but the old shells present quite a different appearance, having more rounded shoulders and an inequilateral outline.

Very young shells of, say, 20 mm. height are difficult to separate from the young of G. huttoni. The teeth of G. robusta, however, are slightly thinner and more horizontal, the hinge-line is narrower, and the anal sinus somewhat shallower. The full-grown shell is more inflated than G. huttoni, the hinge-line is longer, the anal sinus much weaker, and the teeth are longer and more nearly horizontal. The flattening of the posterior margin and its extension downwards give the shell a suggestion of a shortened Cucullaea, an effect strengthened by the horizontality of the outer teeth. Add to this the fact that the type of Cucullaea ponderosa was lost, and we have a fine little pitfall for the palaeontologist. Fortunately, the missing shell has been found, so the error can be corrected. The specimen used by Suter (1914, p. 36) for his description of C. ponderosa (and now in the Dominion Museum) is a Glycymeris robusta. It measures 102 mm. high, 94 mm. long, and 80 mm. thick (both valves). The measurements and locality given by Suter are taken from Hutton's description, and it will be seen that, while the height of both is 102 mm., the length of the Cucullaea is 109 mm., which can hardly be said to “ answer very well” to that of the 94 mm. length of the Glycymeris. The locality of the shell is unknown, but it may be Hutton's G. globosa from Hicks Bay (1873, p. 28).

In an unpublished “ List of Tertiary Mollusca in the Canterbury Museum ” Hutton gives a photograph of a shell from Porter River which., he identified as Cucullaea ponderosa. It is almost certainly a Glycymeris robusta.

Glycymeris cordata (Hutton). (Plate 2, figs. 1, 6.)

1873. Pectunculus (?) cordatus Hutton, Cat. Tert. Moll., p. 28.

1886. Pectunculus cordatus Hector, Outline of N.Z. Geology, p. 51, fig. 6.

Shell comparatively small, heavy, much inflated, roundly trigonal; beaks very broad and high; anterior end broadly curved, sloping steeply from the umbo; posterior end attenuated below; anal depression moderate; sculpture about 35 obscure ribs with linear interstices; ligamental area short and wide, with faint, spaced striae; teeth strong, steeply inclined, not greatly invaded by the area, 8 on each side.

Height (right valve), 34 mm.; length, 31 mm.; thickness, 15 mm.

Lectotype in collection of N.Z. Geological Survey.

Locality.—Wairoa River, Nelson, in large numbers in a brown sand at the mouth of the Wairoa Gorge.

This species is easily identified by its somewhat small size, and the very large, broad beak.

Records to be eliminated from N.Z. Geol. Surv. Pal. Bull. No. 8:—

Page 59. White Rock River, loc. 165 = G. globosa (worn).

Page 69. Left bank, Waitaki River = G. waitakiensis n. sp.

None of the other specimens recorded by Suter could be found, so that no example of G. cordata was seen from, other than the type-locality.

Glycymeris hurupiensis n. sp. (Plate 2, figs. 4, 5.)

Shell large, heavy, inflated, subquadrate when young but becoming obliquely subrhomboidal at maturity; beaks very prominent, anterior dorsal margin long, sloping gradually to the somewhat narrowly-convex anterior margin; posterior dorsal margin shorter, posterior margin broadly

convex; anal depression moderate; sculpture about 30 broad, flat radials with linear interstices generally obscured towards the edge of the adult by strong, waved growth-lines; inner margin coarsely crenate; ligamental area long and wide, with about 6 lightly-incised ligamental lines; teeth of variable strength, 10–12 on each. side.

Height of holotype (right valve), 58 mm.; length, 63 mm.; thickness, 25 mm.

Localities.—

1037—Sandstone, Hurupi Creek, Palliser Bay.

1039—Basal grits, Whakapirihika, east shore, Palliser Bay.

Holotype in collection of N.Z. Geological Survey.

This species may be distinguished from G. huttoni by its fewer and broader ribs, by its less-pronounced anal depression, and the ovate shape of the adult shell.

Glycymeris kaawaensis n. sp. (Plate 2, figs. 2, 3.)

Shell large, heavy, inflated, rounded, trigonal almost equilateral; beaks very prominent,. anterior dorsal margin sloping fairly steeply to the convex anterior end; posterior dorsal margin short, posterior end broadly convex; anal depression very weak; sculpture 30–35 broad, flat ribs with linear interstices, crossed by strong waved growth-lines towards the margin; ligamental area moderately long and very wide, with 6 somewhat shallow ligamental grooves; teeth short and stout, posterior ones curved; the holotype has 17 in front and 13 behind, 5 at each end free of the area (this, however, seems an exceptionally large number, as paratypes have as few’ as 3 whole, teeth at each end and 2 or 3 rudimentary ones truncated by the area).

Height of holotype (right valve), 61 mm.; length, 65 mm.; thickness, 27 mm.

Locality.—996—Kaawa Creek.

Holotype in collection of N.Z. Geological Survey.

Remarks.—This species can be distinguished from G. huttoni and G. hiurupiensis by its much more sloping shoulders, and the short, curved posterior teeth; from the former also by its anal depression being practically absent, and from the latter by its slightly narrower ribs.

This is the shell identified by Suter as G. globosa (Hutton): J. A. Bartrum (1919, p. 104).

Although most of the large shells are thick and heavy, giving a strong resemblance to G. huttom, this does not show the true nature of the species, which is much closer to G. manaiaensis. This is shown not only by the shape of the growth-lines of youthful stages, but also by some large individuals which have not become thickened. One specimen, collected by Mr. Bartrum, has a low beak and is very like a large G. manaiaensis. The area, however, is short and broad, as in other Kaawa shells. Viewed externally, the beak is seen to be somewhat narrower, the shoulders are more sloping, and the ribs fewer in number.

Glycymeris manaiaensis n. sp. (Plate 3, fig. 4; Plate 4, fig. 4.)

Shell large, of moderate weight, obliquely ovate, inequilateral, moderately inflated; beaks small, not projecting much above the dorsal margin, anterior end practically a semicircle, posterior end somewhat attenuated ventrally; anal depression absent; sculpture 30-35 flat radials with linear

interstices, becoming obsolete towards the margin, where there are numerous waved growth-lines; ligamental area short and narrow, almost smooth, with three scarcely discernible ligamental grooves; teeth about 10 on each side, fairly short and stout, bent in the middle, where there is on each side a short striated facet with raised edges.

Height of holotype (complete individual). 49 mm.; length, 53 mm.; thickness of one valve, 16 mm.

Holotype in collection of N.Z. Geological Survey.

Remarks.—This species may be distinguished from the three preceding ones by its ovate shape, very much lower beaks, moderate inflation, and small, almost smooth, area.

Localities:—

• 875—Manaia beach. (Holotype.)

• “Whakino, Hawera (Marshall and Murdoch).

• 1018—Cliff half a mile north—west of mouth of Patea River.

• ? 720—“ Upper band of Petane limestone.” (Fragmentary specimen.)

• ? 736—“ Petane and Scinde Island.” (Fragmentary specimen.)

• Lower end of Starborough Greek, Awatere Valley (Thomson).

• 218—Motunau. (Poor specimen.)

• 219—Motunau. (Poor specimen.)

• 126—Awatere Valley.

• Motunau beds, Middle Waipara (Thomson).

• Motunau beds, Lower Waipara (Thomson).

• Motunau beds, Weka Pass (Thomson). (Fragment.)

• ? 41 (red)—Moonlight Creek, Waiwhero Survey District, Westland.

The shells from Whakino, Hawera, are somewhat stronger in the beak than the type, and in some cases have more sloping shoulders. In this respect they approach the variety of G. haawaensis mentioned above. The general affinities are, however, with the Manaia shell.

Although the shells are not at all alike, this species has generally been identified as G. laticostata. This seems to have been brought about by an identification made by Zittel. The figure he published is that of an equilateral shell with flat ribs and wide shoulders. It is neither G. laticostata nor manaiaensis, but apparently belongs to Glycymeris sp. [see below, p. 74 (d)].

Glycymeris rapanuiensis n. sp. (Plate 3, fig. 1; Plate 4, fig. 1.)

Shell fairly large, not heavily built, disc longitudinally oval, inequilateral; beaks fairly prominent; anterior dorsal margin almost horizontal, anterior end broadly convex; posterior end slightly sinuated above by the anal depression, which is bounded ventrally by a low ridge running from the umbo and making a blunt angle in the posterior margin; sculpture, about 26 very broad flat ribs with linear interstices obscured toward the margin by waved growth-lines; ligamental area small, with 4 lightly incised ligaraental grooves; teeth short, curved, with short striated facets at the angle.

Height of holotype (right valve), 45 mm.; length, 52–5 mm.; thickness, 16 mm.

Holotype in collection of N.Z. Geological Survey.

Locality.—895—Mouth of Rapanui River. (Collected also by Mr. L. Grange.)

Localities:—

• 239—“ Fan coral bed, Porter and Thomas Rivers, Trelissick Basin ” (McKay, 1879). (Holotype.)

• 237—“ Upper part Mount Brown limestone,” Trelissick.

• 238—“ Mount Brown limestone, Coleridge Creek,” Trelissick.

• 449—“ Lower beds, Trelissick Basin ” (Enys, 1880).

The matrix and preservation of this shell are similar to that of the holotype, so it is probably from the same horizon, and not from lower beds as, stated in McKay's manuscript.

The species is distinguishable from the others of the group by its wider beaks and greater inflation towards the margins.

Glycymeris waipipiensis n. sp. (Plate 5, fig. 5; Plate 6, fig. 5.)

Shell very large, regularly inflated, beaks wide and prominent, outline almost circular, anterior regularly rounded, posterior slightly straightened above; sculpture consisting of very fine radial riblets upon a system of obsolete narrow ribs, about 60 in number; waved growth-lines are prominent towards the margin; inner margin very finely crenate; ligamental area moderate, closely grooved: teeth” small,. 7 on each side free of the area; anterior muscular impression only slightly larger than the posterior.

Height of holotype (complete individual), 77 mm.; length, 79 mm.; thickness of one valve, 27 mm.

Holotype in the collection of Dr. Marshall.

Localities:—

Waipipi (Marshall). (Also collected by Murdoch.)

996—Kaawa Creek (small specimens). (Also collected by Bartrum.)

This species is much larger than any of the others in the Axinea group, described in this paper. It is intermediate in character between G. trelissickensis and G. shrimptoni. Small specimens would be distinguishable from the former by their more prominent and narrower beaks, and from the latter by their slightly stronger beaks and higher shoulders.

Glycymeris shrimptoni n. sp. (Plate 5, fig. 3; Plate 6, fig. 3.)

Shell of moderate size, inflated, beaks low; outline almost circular; anal depression obsolete; sculpture—the whole disc is covered with fine closely—placed radial riblets, about 6 per millimetre, superimposed upon narrow obsolete ribs each bearing about 10 of the lines at the margin, near which especially there are concentric growth-lines; inner margin finely crenate; ligamental area moderate, closely striated by 8 grooves; teeth small, 7 on each side free of the area; muscular impressions subequal.

Height of holotype (left valve), 44 mm.; length, 43 mm.; thickness, 15 mm.

Holotype in collection of N.Z. Geological Survey.

Localities:—

191—Shrimpton's, Ngaruroro. River, Hawke's Bay. (Holotype.)

? 231—McLean's, Ngaruroro River. (Very much worn.)

This species is closely related to G. trelissickensis, but the beak is a shade higher and has a narrower angle; there is also less inflation towards the margins.

Some specimens develop a certain amount of obliquity, but they can always be separated from such species as G. callaghani and O. waitakiensis by their wider shoulders.

In N.Z. Geol. Surv. Pal. Bull. No. 8, p. 19, this species is listed as G. striatularis (see below, p. 77).

Glycymeris waitakiensis n. sp. (Plate 5, fig. 2; Plate 6, fig. 2.)

Shell of moderate size, fairly solid, roundly trigonal almost equilateral, inflated; beaks broad, prominent, but only moderately projecting above the hinge-margin; anterior end steeply sloping above, broadly rounded below; posterior end similar, slightly attenuated ventrally; sculpture- the surface is almost smooth but weathering shows very narrow radials corresponding to the fine crenulations of the inner margin; ligamental area short and broad, closely striated by 7–8 grooves; teeth small and fine, about 12 on each side, 6 of which are free of the area.

Height of holotype (left valve), 39 mm.: length, 40–5 mm.; thickness, 15 mm.

Holotype in collection of N.Z. Geological Survey.

Locality.—483—Hutchinson's Quarry greensand, Wharekuri (McKay).

Material, one specimen, in very good preservation.

Remarks.—This shell may be distinguished from G. trelissickensis by its trigonal shape, and from G. callaghani by its approach to an equilateral disposition.

Listed by Suter in N.Z. Geol. Surv. Pal. Bull. No. 8, p. 69, as G. cordata (?), in Mr. Uttley's collection.

Glycymeris. callaghani n. sp. (Plate 5, fig. 1; Plate 6, fig. 1.)

Shell large, solid, inequilateral, obliquely ovate, inflated; beaks moderate, narrow: anterior end semicircular; posterior end attenuated ventrally: sculpture-surface covered with very fine radial riblets, underlain by obsolete primary ribbing, showing plainly on weathering, these ribs are about 50 in number; inner margin with crenulations of moderate size; ligamental area short but wide, closely striated by 8–10 well-incised grooves; teeth fairly strong; muscular impressions subequal, the posterior with a very strong ridge in front of it.

Holotype in collection of N.Z. Geological Survey.

Height of holotype (right valve), 50 mm.; length, 51 mm.; thickness, 18 mm.

Localities:—

154 (in part)—Greensand, Callaghan's Creek, Kanieri district (N.Z. Geol. Surv. Rep. No. 9, 1877, p. 84). (Holotype.) (Collected also by Mr. Bartrum.)

649—Paparoa Rapids, Wanganui River, (The beaks of these specimens are broader than those of the type.)

? 899—Taumatamaire, Awakino. (A small specimen filled with matrix.)

This species may be distinguished from others of the group by its obliquity. The outline is like that of G. manaiaensis of the globosa group, but the fine ornamentation and closely grooved area easily distinguish it.

Dr. Henderson kindly procured some Callaghan's Creek specimens from the Reefton School of Mines. These show the interior clearly. The ridge in front of the posterior muscular impression is stronger than in any other species of the genus.