210 EBURNA. 



a regular channel out of which arises the preceding whorl : The 

 species are all largely umbilicate, but in some of them the um- 

 bilicus is covered or filled, more or less completely by the callous 

 inner lip : the umbilical region is defined by a strong rib. A 

 thin, dark brown epidermis, sometimes translucent, covers the 

 living shell, but cabinet specimens are usually denuded of this, 

 exhibiting upon an ivory-white surface, spots arid maculations 

 of orange-red. The aperture is usually white, sometimes tinged 

 with violet upon the columella. This pattern of coloring is most 

 uniform throughout the genus ; but the species are distinguished 

 by modifications of the arrangement of these color spots, as well 

 as by the differences of shoulder and umbilicus. None of the 

 species are strictly banded, although in some the coloring coal- 

 lesces into irregular revolving masses. The coloring reminds 

 one strongly of Phasianella* whilst the shell, except for the want 

 of its characteristic groove and tooth recalls the genus Pseudo- 

 liva one of the species of which was formerly erroneously 

 referred to this group. The surface of the shell is invariably 

 smooth, devoid of the sculpture of ribs, strhe,.tuberculations, etc. 

 The operculum is ample, filling the aperture. The Eburnae are 

 natives of the tropical seas of the Eastern hemisphere. 



If we observe the rule of taking the first species as the type of 

 a genus, Eburna, Lamarck must become a synonym of Ancillaria, 

 his first species being A. glabrata: Lamarck's assemblage of 

 species, however, clearly indicate his intention. Naturalists have 

 done much to render science and themselves contemptible by 

 expending their time upon the nomenclature, instead of the 

 structure and habits of animals. Ebunio. Lamarck is well under- 

 stood and will answer my purpose. 



I commence with those species showing the least, shoulder, 

 ending with those in which it is most strongly defined. My 

 illustrations are mainty derived from'Sowerby's Thesaurus Con- 

 chyliorum : Reeve has also monographed the genus is his Con- 

 chologia Iconica. 



* Or of the ecclesiastical group of Mitrse, such as M episcopalu, 

 ficatts, papalis, cardinalts, etc. 



