XÇJ2 Art. 1. — M. Yokoyauia : 



anterior. Anterior and posterior ends rounded, the former passing 

 insensibly into ventral margin, while the latter is oblique and forms 

 a rounded angle with the same. Hinge nearly straight, with three 

 or four short oblique teeth in front and about seven almost sub- 

 horizontal teeth behind, the space between being either smooth or 

 provided with a few indistinct granules. Area very narrowl^' 

 triangular. Surface with an obtuse posterior carina and a broad 

 mesial depression which makes ventral margin straight or even 

 somewhat excavated. The sculpture consists of subequal radiating 

 ribs which are flatly rounded, broader than interspaces and number 

 a little more than thirty; some of these ribs show a narrow longi- 

 tudinal groove and a tendenc}^ to split. Occasionally some inter- 

 spaces are unusually broad in which case there is usually an inter- 

 stitial riblet, though only near the margin. Length 5.1 millim. 

 Height 3 millim. Deptli 1 millim. 



The occurrence of this shell is quite noteworthy, as related 

 forms have lutherto been found only in the Eocene, for example, 

 Cuculhria aldrlchi Dall (Tert. ]'\auna Florida, IV. pi. 32, fig. 10) 

 in the Eocene of Florida and Giicullarla gracUis Desli (Anim sans 

 Vert., I, pi. 69, figs. 22—24) in the Paris Basin. 



Fossil occurrence. — Shito. 



Family Limopsidae. 



Genus I.I!»10PSIS. Sasso. 



33S. Zjitiiopsis tvootïtvfirdi, A. Adams. 



PL XVII. Fig. 5. 



Limopsis wooda-anli. Adams, Proc. Zool. Soc. Loncl., 18G2, p. 231. Duuker, lud, 

 Moll., p. 237, p]. XVI, figs. 5, 6. Pilsbry, Catal., p. 150. Tokiuiaga, Foss. Env. 

 Tokyo, p. 62. 



Shell thick, convex, roundly ovate, about as long as high, 

 somewhat oblique, rounded in fi-ont, rounded or obliquely sub- 

 truncate behind. Surface with numerous, rounded, radiating 

 riblets alternately large and small, separated by broader interspaces 

 and crossed by incremental lines which make them somewhat 



