K,>-m1s from the Miura Peninsula and its Immediate North. 59 



Living. — Central and Western Japan: Philippines; Polynesia; 

 Indian Ocean. 



Family Columbellidae. 



Genus Cotutnbella. Lamarck. 



50. Golumbella (Mitrella) dunkeri, Tryon. 



Pi. III. Fig. 15. 



Columella (Mitrrl/a) dunkeri. Teton, Man. Conch., V, p. 129, pi. 49, fig-. 15. 

 Amtjcla rarians. Ddnkee, Malak. Bl., 1860, p. "331, Moll. Jap., p. 6, pi. I, fig. 17. Index 

 Moll., p. 55. Smith, Proc. Zool. Soc. London 1S79, p. 210, pi. 20, fig. 44. Pilsbet, Cat., p. 40. 



This is a smooth, ovately conical shell, sulcate at the base and 

 with the apex acute. The whorls are plano-convex separated by 

 somewhat channelled sutures. The inner lip is smooth, while the 

 outer lip is thickened and coarsely dentate within. Height 15 

 millim. Diameter 6,5 millim. Length of aperture 0,5 millim. 

 Very frequent. 



Fossil occurrence. — Miyata Zone (Kami-Miyata and Shimo- 

 Miyata); Yokosuka Zone (Yokosuka and Otsu). Upper Musa- 

 shino of Shimosa and Kazusa. 



Living. — Northern, Central and Western Japan. 



51. Columbella (Atilia) burchardi, (Dunker). 

 Pl. III. Fig. 7. 



Columbella {Atilia) burchardi. Teton, Man. Conch, V, p. 129, pl. 49, fig. 17. 



Amjcla lurch irdi. Dunkee, Index Moll., p. 55, pl. IV, figs. 3, 4. Pilsbet, Cat. p. 40. 



Two specimens from Yokosuka agree quite well with the 

 figures and descriptions of the above cited species given by 

 Dunker, except in two points, that is, in the spire being son ie- 

 what shorter and the upper whorls showing weak longitudinal 

 plications. Three specimens brought from Shimo-Miyata are 

 somewhat more slender and only one of them shows the longi- 

 tudinal plica' of the upper whorls. Therefore, these plicae can 

 only be taken as a subsidiary character. The fine spiral lines 

 which are mostly incised into the shell are often only visible with 

 a lens. The varicose fold of the outer lip is mostly somewhat 

 distant from the edge and sometimes indistinct. P>road form: 



