180 84 
shell). The posterior side is somewhat higher than the anterior, and both are gently 
rounded towards the ventral side which is straight. The very concave valve is 
flattened in the middle, so that towards the sides rounded keels are formed in 
passing to the anterior and posterior ends. The surface is somewhat glossy, and 
is rough owing to irregular, concentric, coarse lines of growth. The interior of 
the valve is white and slightly glossy. In the left valve, just under the apex, are 
two cardinal teeth of which the anterior one is the smaller; the internal ligament 
is situated immediately behind the posterior tooth. There is also a small posterior 
lateral tooth which is very slightly developed. 
Long. 6 mm., alt. 35 mm., crass. 3°7 mm. 
South of Koh Tulu, 10 fathoms, mud mixed with sand (7/2). 
Unfortunately, the Danish Expedition obtained only the left valve described 
above; it is, however, very characteristic in form, 
Kellya lilium n. sp. 
(Pl. Ill, Figs. 25—26). 
The shell is oblong-ovate, white, semitransparent, dully glossy, rather flat and 
thin. The upper margin slopes from the umbo gradually down on both sides, most 
sharply towards the posterior end, which is somewhat more acutely rounded than 
is the anterior. The ventral side is slightly convex. The umbones, which are not 
especially prominent, are situated somewhat towards the posterior end. At the apex 
the embryonic shell remains as a small, globular, smooth tubercle. Upon the sur- 
face the lines of growth appear as irregular, coarse striz. In the shell-substance 
are seen, both internally and externally, close-set, fine lines which radiate from the 
umbo. The interior of the valves is white and glossy. The hinge-teeth are very 
slightly developed in comparison to the size of the valve; under the apex and some- 
what in front of it there is, in the right valve, a well-developed, prominent, flat, 
triangular and acute cardinal tooth, and a small posterior tooth, more slightly 
developed; between these two teeth there is a triangular pit. The left valve has 
an anterior, long, rather stout, triangular tooth, at the hinder border of which, just 
below the beak, is a small insignificant rudimentary tubercle (in other Kellya- 
species this is developed into a fairly large tooth). Upon the posterior upper 
margin there is a rather small triangular tooth, at the hinder border of which the 
ligament is attached; between the cardinal teeth there is a triangular space. The 
muscular scars are fairly distinct. 
Long. 13 mm., alt. 9 mm., crass. 5 mm. 
The sound of Koh Chang, 3—5 fathoms, soft clay (7/2). N. of Koh Kut, 10 
fathoms, mud (1/2): . 
In outline and external appearance this species somewhat resembles Abra 
alba, Wood. 
