TURRITELLA. ' 157 



underneath; tlie mantle is fringed; in general colour the 

 animal is white, tinted in parts with brownish-grey. 



It inhabits various depths of water, but most commonly 

 affects the more shallow parts. The Turritella seldom lives 

 in those depths where light but dimly penetrates. Is it be- 

 cause he loves the hght for its own sake, or because he 

 would have liis tower-like shell coloured as brightly as pos- 

 sible ? Tor in those few cases where TiirriteUae inhabit 

 more gloomy and impenetrable recesses, the shells are found 

 without any adornment from the solar rays. 



