Marshall. — Tertiary Molluscan Fauna of Pakaurangi Point. 263 



Aet. XXVII. — The Tertiary Molluscan, Fauna of Pakaurangi Point. 



Kaipara Harbour. 



By P. Marshall, M.A., D.Sc. 



[Read before thr Wanganui Philosophical Society, 19th December, 1917 ; received by 

 Editors, 31st December, 1917 ; issued separately, 24th June, 1918.] 



Plates XVIII XXII. 



In a previous paper* a list was given of the Mollusca that had been 

 collected in this locality. Further collections have since been made which 

 have added considerably to the number of the species. Descriptions and 

 figures are given of all the new species. A discussion of the nature of the 

 fauna will be given after the descriptions. 



Vaginella torpedo n. sp. (Plate XXII, figs. 7, 8.) 



Shell of moderate size, 18 mm. by 3"5 mm. Form cylindrical with a 

 conical termination. Slightly compressed at the anterior end. Shell por- 

 cellanous with a shining surface. With a low-power pocket-lens a series of 

 fine longitudinal lines can just be made out. 



Seven good specimens were obtained. Type in the Wanganui Museum. 



Calliostoma gracilis. (Plate XVIII, figs. 1, la.) 



Shell small : height, 7 mm. ; breadth, 10 mm. : trochoidal. Spire short, 

 of 3 whorls. Aperture oval. Columella slightly excavated. Protoconch 

 consisting of 2 whorls. Outline of each whorl of the spire slightly concave. 

 Three small spiral threads near the posterior suture of each whorl and a 

 larger one near the anterior suture. Body-whorl with a large number of 

 fine spiral threads in addition to those on the other whorls. Base with 

 similar small spiral lines, with two large and prominent ones that divide 

 the base into three approximately equal parts. Inner layer of the shell 

 highly nacreous. 



One specimen, in good condition. Type in the Wanganui Museum. 



Heliacus aucklandicus. (Plate XVIII, figs. 2, 2a.) 



Shell small : height, 3 mm. ; breadth, 10 mm. Form obtusely conical. 

 Spire short, consisting of 5 whorls each with a straight outline. Aperture 

 regular. Umbilicus very large, with a strongly crenulated margin. Orna- 

 mentation : Each whorl with 4 beaded cinguli ; the two most prominent 

 of these border the anterior and posterior sutures closely. Base smooth 

 except for irregular ribs radiating outward from the crenulated margin of 

 the umbilicus. 



One specimen only, in a good state of preservation. Type in the 

 Wanganui Museum. 



Epitonium tricinctum n. sp. (Plate XIX, figs. 8, 12.) 



Shell small and slender : length, 8 mm. ; breadth, 3 mm. Spire of 6 

 whorls, but it is not complete. Outline of whorls strongly convex. Suture 

 deep. Aperture not preserved. Ornamentation : On each whorl 3 strong 

 spiral lines. The uppermost of these is the most prominent : it is situated 



* Tran*. N.Z. hist., vol. 49, pp. 447-48, 1917. 



