124 
SPECIFIC 
hinge with two lateral teeth; one primary tooth 
in the right valve^ and two in the left, bifid. 
Born. Mus. C(zs. Tab. 2. Fig. 3, 4. 
Specimen white, yellowish towards the beaks, 
smooth within. 
Inhabits the Indian and American seas. 
Fig. 3. T. planata. 
Shell ovate, compressed, transversely substriate, 
smooth, margin acute. 
Born. Mus. Ccbs. Tab. 2. Fig. 9. 
Specimen purplish red, with paler concentric 
bands, and a tinge of yellow about the beaks 
thin, pellucid. 
Inhabits the English coast. 
Fig. 4. T. cornea. 
Shell orbicular, smooth, horn-colour, trans- 
versely striate. 
Lister Conch. Tab. 159. Fig, 14. 
Specimen within dirty white passing into cine- 
reous ; without bluish white, polished ; transverse 
striae unequally deep ; covered with an olive brown 
epidermis, which is darker in transverse bands, one 
V 9 
