58 POPULAU BRITISH CONCHOLOGY. 



beautiful (even the British examples fine, some of 

 the foreign kinds splendid). They are more or less 

 wedge-shaped_, having one side short and truncated, 

 the others long. Ligament external ; teeth two ; no 

 lateral teeth. Inside edge of the valves beautifully 

 toothed all round. The animal has a tongue-shaped, 

 pointed foot; open mantle; rather short, unequal 

 siphons ; that for ejection, the smaller, simply fringed 

 with ten lobes; the other larger, with the lobes 

 branched. All the species live buried in sand. The 

 British species are — 



B. anatimis : so called from its likeness in shape to a 

 duck's-bill, has the shell decussated at the hinder part 

 with cross striae. On the outer surface of the valves 

 may be seen, through the shining yellowish epidermis, 

 radiating shades of the same bright purple which is 

 seen in its full, unclouded glory within. 



D. poUtiis : rather longer and straighter than B. anatititis, 

 and quite smooth. Prom the apex to the ventral mar- 

 gin of the shell radiates a band of light, on either side 

 of which are arranged streaks of clouded purple, which 

 show more brightly at the poiut or apex, where the 

 thin epidermis is not sufficient to veil its beauty. 



