Fossils from the Miura Peninsula and its Immediate N ] IK 



140. Tellina serricostata, Tokunaga. 



Pl. VII. Fig. 24. 



Tellina serricostata. Tokunaga, Foss. Envir. Tokyo, p. 43, pl. II, %-. 32. 



Shell thin, flattened, transversely ovate, almost equilateral. 

 Anterior margin rounded, posteriorly rostrate with end obliquely 

 truncate; antero-dorsal margin sloping, somewhat convex; postero- 

 basal margin also sloping, slightly concave; ventral margin 

 broadly arcuate, becoming more straight towards the posterior 

 end, or even, shallowly notched near it. Surface with a blunt 

 edge, running from the beak to the postero-ventral corner. The 

 space between the edge and the postero-dorsal margin is only 

 slightly depressed. The sculpture consists of fine concentric 

 lamellar riblets with the interspaces looking like furrows. Beaks 

 small but prominent, directed posteriorly. Main teeth two, the 

 anterior in the right valve consisting of two separate teeth; 

 laterals in the right valve distinct, one on each side. Palliai sinus 

 large and deep, reaching near to the anterior muscular impression 

 and going upward to two-thirds the height of the shell. 



Only two right valves, the larger of which is 26 millim. long, 

 15 millim. high and 35 millim. deep. 



This species shows a close resemblance in shape to Tellina 

 Incarnata L. (Syst. Conch. Cab., vol. X, part 4, p. 126, pl. 29, 

 tigs. 1-5) of the Atlantic, bin the lamellar riblets and the separate 

 anterior main tooth of the right valve are the chief distinguishing 

 characters. 



Fossil occurrence. — Miyata Zone (Kami-Miyata); Naganuma 

 Zone (Naganuma). Upper Musashino of Musashi. 



141. Tellina miyatensis, Yokoyama. 



Pl. VII. Fig. 18. 



Shell small, thin, flattened, transversely suboblong, very 

 inequilateral, the anterior side more than double the length of the 

 posterior. Anterior end perpendicularly truncate, posterior 

 rounded, gradually passing into the sloping antero-dorsal margin 



