"[RA Art. 1. — M. Yokoyama : 



26». A.starte liahodatensis, Yokoyama. 

 Astarte hakodatcnsis. Yokoyama, Foss. Minra Peniii., p. 140, pl. XI, figs. 5, 6. 



This species is smaller and higher in form than the preceding. 

 Its description is found in my work above mentioned. 

 Fossil occurrence.- — Shito. 

 Living. — Northern Japan. 



Family Crassalellidae. 



Genus CKASSATEL,L,A, Lamarck. 



264. Crassafella oblonyafa, Y'okoyama. 

 Crassatella oblongata. Yokoyama, Foss. Miura Penin., p. 142, pl. XI, figs. 8, 9. 



A few young specimens which are somewhat flatter and more - 

 coarsely grooved on the surface than the adult ones. The largest 

 obtained is a right valve, 9 mihim. long, 6.5 miUim. high and 2 

 millim. deep, with concentric grooves about seventeen in number. 



Fossil occurrence. — Shito. Lower Musashino of Mij^ata and; 

 Koshiba. 



265. Crassatella tiatta, Adams et Eeeve. 



PI. Xni. Fig. 8. 

 Crassatella nana. Adams and Eeeve, Voy. Samarang. Moll , p. 81, pl. XXIII, fig. 2. 

 A single right valve. Shell thick, strongly compressed, 

 subequilateral, somewhat pentagonal in outhne, longer than high, 

 rounded in front, truncate behind. Postero-dorsal margin straight, 

 sloping, gradually passing into posterior margin with a curve; 

 ventral margin broadly arcuate with inner side crenulate and 

 postero-ventral corner obtusely angulate. Surface with concentric 

 furrows. Beaks small, pointed, with an obtuse edge running to 

 postero-ventral corner. Main teeth two, oblique with lower ends 

 towards front and a triangular ligamental pit behind; anterior 

 lateral tooth distinct, elongated. Anterior nmscular impression 

 somewhat pear-shaped, posterior more rounded. Length 15 

 miUim. Height 12.1 milhm. Depth 3 millim. 



