PSAMMOBIA. . 53 



disappointed when we are first attracted by outward specia- 



litieS; and afterwards become acquainted with the insides of 



things. 



The genera including British species belonging to this 



family are — 



I. PsAMMOBiA. — Shell of a flat, oval form, rounded at the 

 front, and rather squared at the hinder end; hinge 

 near the middle, external, and placed on a thickened 

 fulcrum ; teeth two and one ; a very deep sinus in the 

 impression of the mantle. Animal white, with broad, 

 pointed foot, and long narrow siphonal tubes, which are 

 quite divided, haii'y at the sides, and scalloped at the 

 orifices; mantle o]r)en all along and fringed. The 

 Tsammolm live buried in sand or mud. The British 

 species are — 



P. vespertina, or "setting sun .'' shell smooth, clouded with 

 rich purple inside, with light rays; outside marked with 

 wavy bands in rays ; about an inch and a quarter long. 



P. Ferroensis : shell slightly ridged, longer in form, with an 

 angle and slight contraction behind it ; marked with 

 delicate pink, even rays ; an inch and a half long. 



P. Tellmella : shell smooth, oval, orange, with linear rays of 

 pink ; three-quarters of an inch long. 



