ACEPHALA. AI5 
Suett thin and fragile, yellowish-white, sub-globose, a little oblique, 
nearly equilateral ; surface marked only by fine incremental strie, 
which occasionally mark arrests of growth, and by microscopic diverg- 
ing lines. Beaks slightly anterior, swollen, a little elevated above the 
transverse dorsal margin, strongly antrorse, with a decided emargina- 
tion in the outline, in front of them; anterior end compressed ; poste- 
rior half higher than the anterior; dorsal margin horizontal and recti- 
linear, then curving abruptly, it sweeps round the ventral portion in 
nearly a regular circle, a little oblique, however, so as to bring the 
most depending portion behind the middle. Valves ventricose. Within, 
plain yellowish-white, disk with a dead ground, sprinkled with shining 
punctures; edge minutely lineated. Hinge delicate, without cardinal 
teeth, and with only an oblique, anterior ligamentary groove resting on 
a rib-like support. 
Length an inch and a quarter; height an inch and an eighth; width 
seven-eighths of an inch. 
Inhabits the Tonga Islands. Dr. Pickering. 
Its surface is like L. filan, but its form is more ventricose, and its 
dorsal margin is much less sloping, somewhat alate; and this is one of 
its most striking peculiarities. In form it is more like L. wndata, ex- 
cept that the reverse extremities correspond. 
A Singapore species has the same form, but the beaks are more ele- 
vated, and have a pit before them; the hinge is more delicate; the 
ligament groove is less oblique, and with a less substantial rib-support; 
surface more free from striew. It probably belongs to the genus 
Loripes. 
Figure 525, exterior of the shell; 5254, inside, with the hinge; 5256, 
dorsal view of the shell. 
LucIna RAMULOSA (Gould). 
Testa crassa, scabra, lenticularis, viz obliqua, albida, costulis radianti- 
bus crebré divaricantibus et filis continuis concentricis crebris in- 
sculpta; apicibus elevatis acutis antrorsum versis ; lunula excavatd, 
haud insculpta: cavositas albida vel citrina, incrassata ; cicatricibus 
