94 -A-rt. 6. — M. Yokoyama: 



The only specimen Ave possess lacks the upper portion of the 

 spire, but it seems to have been high-conical. The diameter is 

 •5) millim. 



P^ossil occurrence. — Naganuma Zone (Naganuma). 



Genus Euchelus^ Philippi. 



106. Euchelus fenestratus, Yokoyama. 



Pl. VI. Fig. 2. 



^hell small, thick, globose-conical, imperforate; whorls about 

 live, quickly growing, convex, spirally ribbed and longitudinally 

 •costellated ; spiral ribs three on the penultimate whorl, eight on 

 the last, with about equal interspaces, crossed by costella?, divid- 

 ing the interspaces into square pits, and making the ribs granose. 

 Sutures impressed. Periphery rounded. Base convex, with an 

 interstitial riblet between some ribs and developed only behind 

 the outer lip. Columella smooth. Aperture subcircular. Outer 

 lip thick, denticulate within, about 12 teeth being present between 

 the posterior angle of the aperture and the lower end of the 

 columella. Height and diameter 5 millim. 



This shell of which we possess only one specimen resembles 

 Euchelus ruber A. Adams (Tbyon's Man. Conch. XI, p. 440, pl. 

 67, fig. 79) living near Kamakura and in the Japan Sea, which is 

 however umbilicate and has a greater number of spiral ribs. 



Fossil occurrence. — Yokosuka Zone (Yokosuka). 



Genus thnboniiitu. Link. 



107. Umbonium gigantenm, (Lessom). 



Pl. VI. Fig. 5. 



Umbonium glganteum. Ptlsbry in Tr-jon's Man. Cjnch., XI, p. 454, pl. 58, figs. 17-18. 

 Bunker, Index Moll. Mar. Jap., p. 134. 



liotella gigantea. Lesson, Illnst. de Zool., t. 17, 1831. Kiener, Spec, et Icon. Coq. Yiv., p. 

 •16, pl. 3, fig. 7. Sowerby, Thes. Conch.. V, p. 136, pl. 472 figs. 15, 16. 



Globulus giganteus. Lischke, Jap. Meeresconch., vol. Ill p. 63. 



A fractured specimen of a large, solid, depressed Umbonium 

 with flattened to somewhat concave smooth whorls, rounded 



