Vidurian FosslU, Pari XV. lUl 



Fain. Plelkotomidae. 



Genus PleUPOtoma, Lainarck. 



Pleurotoma myeeana (Tate M.S.^), sp. nov. (Plate XIT., Fig. 7.) 



Defteription . — Shell of moderate dimensions, pyramidally ovate ; 

 body whorl approximately equal in length to the spire. Prototonch 

 large, consisting of two and a half smooth, inflated whorls, followed 

 l)y six angiilate whorls, with well marked sutureis ; also a median 

 nodulose keel medially grooved, below which are one ot two strong, 

 spiral threads. Last whorl with five rounded, spiral ridges inter- 

 lineated with fine, secondary lirae. The whole shell surface finely, 

 longitudinally costated with growth-lines. Aperture of medium size, 

 rather broad, pyriform ; outer margin arcuate ; sinus shallow, 

 situated just below the suture ; cnlumellar margin smooth, slightly 

 twisted in front; anterior canal short. 



Dimen<sions. — Length, 22 mm. ; greatest width, 9.25 ujm. ; widtli 

 of aperture, 4 mm. 



Observations. — The nearest species to the above in fossiliferous 

 deposits seems to be the pliocene species Pleurotoma tuherculata, 

 Kirk,"^ from Petane, N. Zealand. TTiat shell, however, is more' fusi- 

 form, the carinal tubercles not grooved, and the aperture propor- 

 tionally broader. A living Australian species, also nearly allied to 

 the present one, but differing in some important particulars, is 

 Pleurotoma armiUata, Reeve.'^ This form has a large and deep sinus, 

 the keel more numerously beaded, and it is altogether a smaller 

 and lighter shell. 



EXPLANATION OF PLATES. 

 Plate XIL 



Fig. 1. — Acmaea octoradiata. Button. Cast of inside of shell in 



ironstone. Tertiary ; janjukian, Nat. S'ize. 

 Fig. 2. — A. ortoradiata, Hutton. A cast in wax of the internal 



mould of the ironstone fossil, showing external ornament. 

 X 2. 

 Fig. 3. — Astralium [Imperator) iiiulosin/i, sp. nov. Superior aspect 



of shell. Tertiary ; IJalcombian. Altona Bay Coal-shaft. 



Holotype. Nat. size. 



1. This species was appropriately desig:nated in M.S. by Prof. U. Tate (see this journal, vol. iii.. 

 1891, p. 57—Surcula .Snyceana) in honour of the late Mr. O. A. Sayce, A.L.S., who collected anionust 

 the fossils .shells in coiiiiianv with Prof. Tate and others in the Gippslaiid Lakes district. 



2. Trans. N. Zealand List., vol. xiv., p. 409. Hutton, Alacleay Mem. Vol., I-inn. Soc. N. S. 

 Wales, 1893, p. ."iO, pi. vi., fig. 29. 



3. Reeve, Iconographia, 1843, vol. i., fiir. 170. 



