99 195 
tion into the somewhat truncated posterior side. The umbo is situated towards 
the posterior side and the apex bends towards it. The umbo is fairly high and 
slopes gradually downwards on both sides. The surface is coyered with close-set, 
regularly-arranged, concentric striz; some of these terminate at the place on the 
posterior side where they bend upwards, and only every other is continued up- 
wards to the area which is limited by a small keel. The interior of the valve 
is pure white; in the right valve (which alone is at hand) the lateral teeth are 
strongly developed on each side; there are two cardinal teeth, of which the hinder 
is the larger. The pallial sinus is large and deep, but appears very indistinctly 
upon the glossy inner surface. 
Long. 5:5 mm., alt. 5 mm., crass. 3 mm. 
West of Koh Kut, 30 fathoms, sand, mud. 
As the left valve is not known IJ cannot decide with certainty whether this 
species belongs to the subgenus Arcopagia. 
I have ventured to associate with the name of the present species that of Mr. 
Epa. Smiru, to whom malacological science is indebted for so many valuable works. 
Tellina (Merisca) Martensi n. sp. 
(PI. Ill, Figs. 40—42). 
This shell is small, white, rather thick-valved and triangular in outline. The 
surface is ornamented with more or less close-set, raised, concentric lamelle, the 
interspaces are smooth and somewhat glossy. The umbones, which are situated at 
about the middle of the shell, are pointed and prominent, and slope rather abruptly 
downwards on both sides. The somewhat swollen anterior end passes gradually, 
and with rounded outline, into the ventral side which is convex and forms a rather 
acute angle with the hinder side. The posterior part exhibits a slight “Tellina- 
curvature.” The interior of the valves is white and glossy. In the right valve 
there are two cardinal teeth, and two oblong, strongly developed lateral teeth; in 
the left valve there are no lateral teeth and of the two cardinal teeth the anterior 
is the larger. The pallial sinus is large and deep. 
South of Koh Kut, 17—20 fathoms, mud (‘/2). (Singapore, 2—3 fathoms, coral- 
reef; 3/2): 
Long. 3°55 mm., alt. 3 mm., crass. 2 mm. 
This little characteristic Tellina-form must be referred to DALUw’s section 
Merisca of the subgenus Arcopagia; it somewhat resembles the much larger T. (Merisca) 
crystallina, Wood,! from South Carolina, but that species is longer, and has a more 
decided rostrum. The specimens at hand show that the species varies considerably 
in regard to form and the density and height of the lamellae. I have named this 
species after the late Professor Ep. v. Martens, the first zoologist who gave us a 
fauna of the Mollusca of Siam, and to whom malacological science is indebted 
for many profound and yaluable papers and works. 
1 Proceed. Unit. Stat. Nat. Mus., vol. 23, 1900, p. 311, pl. 2, fig. 10. 
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