Marshall. — The Wangaloa Beds. 453 



Heliacus conicus u. sp. (Plate XXXIV, fig. 10.) 



Shell small, conical, 7 mm. by 7 mm. Sculpture consisting primarily of 

 3 prominent cinguli on each whorl : the highest is close to the suture, and 

 is distinctly beaded ; the middle cingulus is the widest, but it is less dis- 

 tinctly beaded ; there are 4 or 5 other cinguli less marked and less beaded. 

 Base with numerous cinguli cut up by fine oblique radiate sulci. Umbilicus 

 moderate, margined by a stout and crenulate cord. Spire moderate, conical, 

 higher than the aperture. Outline of whorls convex, suture impressed. 

 Whorls 5. Protoconch of 2 small whorls. Aperture not distinct. 



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

 Museum. 



Two fossil species of this genus have hitherto been found in New Zea- 

 land. They occur in the Target Gully beds, near Oamaru, and the genus 

 is also Recent. Suter states that the genus is of Tertiary occurrence. 



Omalaxis planus n. sp. (Plate XXXIV, fig. 11.) 



Shell discoid, small, 10 mm. by 3 mm. Spire of 5 whorls, almost flat, 

 but body-whorl slightly concave. Suture much impressed, almost canali- 

 culate. Upper whorls with a smooth surface ; body-whorl with 2 moderate 

 carinae round the periphery. A strongly beaded line surrounds the suture. 

 From the beads small elevated lines with a curved form extend across the 

 greater part of the body-whorl. Umbilicus large, surrounded by a prominent 

 crenulated margin. 



A single specimen, well preserved. Type in the Otago Museum. 



Omalaxis has not previously been obtained in the fossil state in New 

 Zealand. The genus appears to be restricted to the Tertiary period. 



Heteroterma zelandica n. sp. (Plate XXXV, figs. 20, 21.) 



Small complete specimen, 15 mm. by 8 mm. ; larger specimen, nearly 

 complete, 24 mm. by 17 mm. ; large specimen, 44 mm. broad. Shell large, 

 shortly fusiform. Spire very short. Each whorl with spiral ridges ; those 

 on the whorl next to the body-whorl 7 in number ; interspaces about three 

 times as wide as the ridges, with a faint discontinuous median ridge. Body- 

 whorl large, somewhat angulated above the middle, abruptly contracted 

 into the beak below ; shape above the middle slightly concave ; surface 

 marked by fine lines of growth and with 10 large spiral ridges one-third 

 the width of the interspaces, which have a fine median ridge ; middle of 

 body-whorl with 14 short prominent longitudinal plications ; base of the 

 shell and the beak marked with spiral lines similar to those on the rest of 

 the bady-whorl. Anterior canal long ; the curved lines of growth indicate 

 a shallow posterior sinus of the aperture. 



In the list of the Wangaloa mollusca published last year this species 

 was classed by Suter as Euthriofusus n. sp. (Trans. N.Z. Inst., vol. 48, p. 115). 

 The great similarity between these specimens and those of Heteroterma 

 gabbi, described and figured by Stanton (17th Ann. Rep. U.S. Geol. Surv., 

 1895-96, Part I, p. 1046), caused me to forward my specimens to him with 

 the request that he would compare them with the Californian species. This 

 he has kindly done, and he has sent me some critical notes of great value, 

 which it is advisable to quote : — 



" After comparing the specimens I agree with you that your fossils are 

 similar to Heteroterma gabbi Stanton, though I think there can be no question 

 that they are specifically distinct. I would comment on them as follows : 



