124 S PE C J FI c 



liiuge with two lateral teeth ; one primary tooth 

 in the right valve, and two in the left, bifid. 



Born. Mils. Cces. 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. Mils. Cces. tab. 2. fig. 9. 



Specimen purj)lish red «vith 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 Cui-cli. 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 



