Fossils from the Upper Musashino of Kazusa and Shimosa. lOÖ" 



Fossil occurrence. — Tega (rare) 

 Living. — Central Japan. 



Family Trochidae. 



Genus TROCHUS, Limié, 



161. Troehus stnuit/ei'a, Yokoyama. 

 PL V. Fig. 18. 



Shell small, conical. Whorls about six, shghtly convex, 

 furnished with unequal spiral threads set with numerous, close, 

 pointed, spine-like tubercles. Each whorl has two main threads 

 which divide it into three nearly equal parts with a finer thread 

 on each. Periphery angulate, witli a smooth tliread on it. Base 

 flattened, spirally grooved; grooves several, the outermost the 

 broadest, the other ones being more like impressed lines, although 

 the innermost one or two are somewhat stronger. Aperture (outer 

 lip fractured) roundly quadrate. Height 5 millim. Diameter 

 4 millim. 



A single specimen, but very characteristic by its spinose- 

 tubercles. 



Fossil occurrence. — Shito. 



Genus 1WLINOL.IA, A. Adams. 



162. Mhiolia fastnaniea, Tenison-AVoods. 



PI. V. Fig. 19. 



Minolia taamanica. Tryou, Man. Concli., XI, p. 263, p]. 61, figs. 38 — 40. 

 Margarita {Minolia) tasmanica. Tenison- Woods, Proc. Eoy. Soc. ïasm., 1876, p. 

 143 (1877) 



Shell small, thin, depressed, with a low-conoidal spire. Whorls 

 about five, terraced above, convex below. Terraces horizontal, 

 flat or even somewhat concave, with very fine spiral lines. Convex 

 surface spirally striate; strise equal, close, six on the penultimate 

 whorl. Periphery rounded. Base convex with several close 

 spiral strice. Umbilicus open, with walls funnel-like and outer 

 margin rounded. The walls may be very steep or not; in the first 



