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Volume 48, 1915
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Art. X—Some New Fossil Gastropods.

[Read before the Otago Institute, 7th December, 1915.]

Plate XI.

The following new species, belonging to the genera Pugnellus and Avellana, which appear to occur in Cretaceous strata only in other parts of the world, were obtained from the younger strata of Otago during the past year.

Pugnellus australis n. sp. Plate XI, figs. 1, 2, 3.

Shell of moderately large size, turreted, carinate. Sculpture consists of a conspicuous nodulose spiral rib on the carina, showing 9 nodes on the part of the body-whorl that is not hidden by the very large callosity of the lips. Two other less conspicuous nodulous spiral ribs on the body-whorl. A large number of fine spiral striae on the body-whorl—in, all, about 50. Nodules on the body-carina extend backward as ridges, gradually decreasing in size, and disappearing near the suture. Nodules also extended forward and bent round towards the aperture. Nodules near the callosity of the outer lip less pronounced. Spire of 4 whorls, each whorl convex, with a nearly flat base. Suture linear, slightly canaliculate. Aperture narrowly oval, rounded at the top, but with 2 rudimentary canals at the base. Columella straight. Callosity of the outer lip very large—18 mm. wide. It extends over the top of the spire, and unites with the callosity of the inner lip, and together they cover about half of the body-whorl. The middle part of the outer lip is produced into a prominent rounded claw, with a scaly structure. Columella, straight.

Height, 47 mm.; width, 40 mm.

Type and two paratypes in the Otago University Museum, Dunedin.

Locality.—Wangaloa, South Otago.

The genus Pugnellus has hitherto been recorded from Cretaceous rocks only. It has rather a wide occurrence, which is, however, almost wholly circum-Pacific. It has been found in the Ripley and the Chico beds of California, the Ariyalur of India, the Quiriquina of Chile, the Cazador of south Patagonia, in the Cretaceous of Borneo and of Libya. It has not yet been found in Australia.

The genus is closely allied to Conchothyra; in fact, Wilckens considers the genera may be identical.* Conchothyra is well known to occur in beds at the Selwyn Rapids, Waipara, and the Trelissick basin. It is always associated, with a Cretaceous fauna.

Avellana paucistriata n. sp. Plate XI, figs. 4, 5, 6, 7.

Shell small, nearly globular. Sculpture a series of about 17 small spiral lines on the body-whorl. Near the base these are narrow, with nearly equal interstices. Towards the middle of the body-whorl they are much wider and flat, with narrow interstices. Those near the suture can hardly be distinguished. In one well-preserved specimen 7 of these spiral ribs are distinct near the base, but there are none on the middle of the whorl, and an additional 2 are developed close to the suture. The interstices are marked by minute transverse ridges. In some specimens 5 spiral lines can be distinguished on the 2nd whorl. Spire short, consisting of 4 whorls.

[Footnote] * O. Wilckens, “Die Lamellibranchiaten, Gastropoden, &c, der oberen Kreide Sudpatagoniens,” Ber. naturf. Gesellsch. Freiburg, Band 15, p. 20, 1907.

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Figs 1–3Pugnellus australis n. sp. Natural size.
Figs 4–7Avellana paucistriata n sp × 2 ½.
Figs 8, 9Avellana curta n. sp × 2 ½.
Figs 10, 11Avellana tertiaria n sp × 2 ½.

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Each whorl distinctly convex and decreasing rapidly in size. Spire only half the size of the aperture. Suture rather deep. Aperture ovoid, narrowing behind, nearly straight except for an indentation near the base. A wide callosity borders the whole of the outer lip. Inner lip callous. Columella with 2 prominent folds near the base. In one specimen some denticulations can be distinguished on the inner border of the outer lip.

Height, 6 mm.; width, 5 mm.

Six paratypes in the Otago University Museum, Dunedin.

Locality.—Wangaloa, South Otago.

Specimens sent to the National Museum, Melbourne, with the request to determine whether the mollusc was Avellana or Eriptycha were returned with the statement that they should be classified with Eriptycha. Mr. H. Suter has, however, kindly examined the specimens, and he agrees with me that they belong to Avellana.

The genus Avellana does not appear to have been collected outside of European countries previously. Thus Cossmann records it from the Albian, and Cenomanian of France, Belgium, and England. It does not appear to have been collected from horizons higher than this. The closely allied Eriptycha, which is typical of the Upper Cretaceous, occurs somewhat widely in the highest Cretaceous of the circum-Pacific region—viz., California, Chile, and Patagonia; and Mr. F. Chapman kindly informs me that an undescribed species has been found in the Miocene of Victoria.

Avellana curta n. sp. Plate XI, figs. 8, 9.

Shell small and globular. Sculpture of body-whorl consisting of about 27 spiral ribs of approximately equal size, flat on the top. Interstices rather narrow, and minute narrow transverse ribs cross the interstices. Sculpture of 2nd whorl 7 spiral ribs. Spire very short, consisting of 4 whorls, each of which is very slightly convex. Suture not strongly marked. Aperture oval. Callosity of the outer lip broad, but apparently without denticulations on its inner surface. Inner lip callous, but the form of the columella is not distinct.

Height, 9 mm.; width, 7 ½ mm.

Three paratypes in the Otago University Museum, Dunedin.

Locality.—Wangaloa, South Otago.

This species is very similar to A. tertiaria from Hampden, but is distinguished from it by its larger size, shorter spire, more irregular ornamentation, and by the absence of denticulation of the outer lip.

Avellana tertiaria n. sp. Plate XI, figs. 10, 11.

Shell small, nearly globular. Sculpture 29 flat spiral ribs on the body-whorl. They are of approximately equal size, though somewhat narrower near the base. Interstices narrower than the ribs, and crossed by numerous minute transverse ridges. Spire short, consisting of 4 whorls about ¼ the length of the aperture. Ten small spiral ribs in the 2nd whorl. Outer lip with a callosity 1 mm. wide, marked with 7 striations parallel to ita margin. Outer lip marked internally with 13 denticulations, three of which are much larger than the others. Inner lip callous, but the callosity extends only slightly from the aperture. Columella nearly straight, with 2 narrow folds near the base.

Height, 7 mm.; width, 6 mm.

Holotype, Otago University Museum.

Locality.—Onekakara, Beach, near Hampden.