ACEPHALA. All 
Length three-fourths of an inch ; height half an inch; breadth one- 
fourth of an inch. 
Inhabits Singapore. 
The outlines are all gently rounded, and it is otherwise distinguished 
by its dead, sallow white colour, and its sculpture. 
Figure 520, lateral view of the shell; 520, interior, with the hinge; 
520 b, dorsal view of the shell. 
Donax TINcTUS (Gould). 
Testa crassa, ovato-trigona, cuneata, versicolor, scilicet incarnata, stra- 
minea vel violacea, striis lamellosis concentricts posticé flexuosis in- 
sculpta; apicibus feré medianis ; margine interior integro ; dente 
laterali valido ; dente antico obsoleto. 
Donaz tinctus, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 255. 
June 1850. Expedition Shells, 81. 
Suet thick and solid, triangular, wedge-shaped, with the beaks 
nearly central, the angles rounded, and the two sides nearly equal. 
Surface marked with regular concentric lamellar strie, which, at the 
posterior end, become delicately flexuous, giving this extremity a 
rugose aspect. The colour varies; one specimen is pale carmine, much 
more intense at the beaks, and of the same tint in the interior; another 
is straw-coloured; another a pale violet-colour, slightly radiated, 
clouded with deep violet within. The posterior lateral tooth is fully 
developed, but the anterior one scarcely appears. The margin is 
entire. 
Length eight-tenths of an inch; breadth two-fifths of an inch; height 
seven-tenths of an inch. 
Habitat unknown. 
The specimens I have examined vary very much in colour, yet 
