42 THE BLACK MITER. 



part of the preparation, but the thorough cleaning of 

 the shell is indispensable, and should be attended to 

 as soon as possible after specimens are gathered. 



OliveUa bcetica^ Cpr. , be^-ti-ca, Fig. 21, has a more 

 slender shell than the last species, and is smaller in 

 all respects. Some specimens are larger than the 

 engraving, but the spire is always quite tapering, 

 and the shell is usually thin and delicate. The 

 color varies, but it is generally brown or bluish, 

 sometimes diversified with yellow stripes. 

 p^g-2i- A short, yellowish variety is sometimes called 

 OliveUa iiitorta^ but it seems to me that it does not 

 deserve that name, which is applied to a species found 

 in the Gulf of California. I think all our specimens 

 may be classed under one or the other of the two 

 main species. 



Most of the Olives live in warmer waters than those 

 which bathe the west coast of the United States, and 

 some of them from tropical seas are ver}' beautiful 

 and richly colored. 



Mitra maura^ Swains., Mi^-tra mau'-ra, is a dusky 

 relative of the beautiful Miter Shells which are found 

 in the vicinity of Australia. Some of those southern 

 shells, like the Pope's Cap, and the Bishop's Cap, 

 look exceedingly gay with their yellow, 

 white, and scarlet markings and their crown 

 of graceful points. 



Our species, however, as shown in Fig. 

 22, has a plain, smooth shell, while its color 

 is almost black, and it is wholly devoid of 

 the gay trimmings of its relatives. The 

 shell is strong and firm, spindle-shaped, 

 obscurely marked by lines of growth and 

 Fig 22. spiral threads. The columella is ridged by 



