116 UNIVALVES. 



semblance of colour have occasioned some 

 specimens to be described as Turbines. 



GENUS. HALIOTIS* 



SEA-EAR OR EAR-SHELL. 



Generic character. Shell univalve, dilated, 

 ear-shaped; spire flat, lateral, retuse, nearly 

 concealed ; aperture almost as large as the shell ; 

 the disk,* excepting in one or two species, has a 

 series of perforations parallel to the columellar 

 margin. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The ear-like shape, the flattened spire and the 

 row of perforations on the disk readily distinguish 

 this genus from every other. The outside of the 

 shell is generally rough, worn or covered with 

 marine substances. The inside is enamelled with 

 mother-of-pearl, exhibiting a beautiful iridescent 

 play of colours. Each period of the shell's in- 

 crease is marked by a new hole, and till the final 

 addition is made, there is a notch in the last per- 

 foration in which the animal places its siphon. 



* Plate V. figure 2. 



f Disk, a rounded surface, from the Latin discus, a dish or 

 platter. 



