HALIOTIS. 77 



cavity of spire not concealed, but near the posterior end ; nacre sil- 

 very ; muscle-scar not distinct. 



Indian Ocean. 



Group of H. diversicolor. 



Shell oval evenly convex, the two sides equally curved, scarcely 

 carinated at the row of holes ; spirally striated ; apex very close to 

 the posterior margin. 



Japan to Australia. 



Group of H. iris. 



Shell rather large, oval, convex, carinated at the row of holes ; 

 apex subterminal ; nacre dark, the muscle scar roughened ; cavity 

 of spire minute, concealed; peristome continuous. 



New Zealand. 



Group of H. rugosoplicata. 



Shell oval, light, convex, radiately corrugated above, spirally 

 ribbed below the row of holes ; nacre silvery. Holes circular, 

 slightly tubular, 6 to 8 in number. 



New Zealand; S. Australia. 



Group of H. mar ice. 



Shell oval, spire small, subterminal, surface with strong spiral 

 ribs ; inside silvery, muscle-scar not distinct ; holes 6, circular, a 

 little tubular. 



Australia. 



Group of H. midce. 



Shell rounded, convex, spire large ; nearly smooth or with radiat- 

 ing lamellae or wrinkles, spiral sculpture wanting or obsolete ; 

 muscle-scar distinct or not ; young with a blood-red spot inside the 

 spire ; a carina at the row of holes. 



Cape of Good Hope. 



Group of H. ncevosa. 



Shell rounded, flattened, the spire large; surface having spiral 

 striae (sometimes obsolete) and usually radiating waves ; a carina? 

 at the row of holes ; inside silvery. 



New Zealand ; Australia. 



