3 ERATO. 



it is very like Ct/prtra. in external appearance, even to the tila- 

 mentous processes of the mantle-lobes, and it is evident that the 

 growth of these processes has caused an inequality in the applied 

 surface of the lobes, sometimes forming pustules on the shell in 

 Eratopnis, in precisely the same manner as in the Pustularia 

 group of Cypraea. Reeve remarks in the introduction of the 

 " Monograph of Erato " (Conchologia Iconica), that in Erato, 

 unlike Marginella, the columella is not plaited from an early 

 stage of growth, but that the denticulations are added at 

 maturity ; in other words, the}^ are denticulations and not true 

 plaits. If this were so, it would be another character in common 

 with Cypraea, but my observation leads me to the conclusion 

 that it is not entirely true. I find the plaits on the columella 

 in young specimens of several species, but in addition, there is 

 developed on the inner lip, in the adults only, a series of dentic- 

 ulations like Cypr&a, and at the same period changes sometimes 

 occur in the appearance of the plaits caused by the deposition 

 of calcareous matter upon and between them, so that these come 

 to resemble the denticulations situated above them. Undoubtedly 

 Erato, through Eratojisis, conchologically connects Marginella 

 with the Trivia group of Cypraea ; the balance of characters 

 seems to indicate a rather closer relationship, on the whole, with 

 Marginella but if future investigations shall show that the 

 species of Erato really possess the dentition assigned to the 

 group, then it would perhaps be better to remove it to the 

 Triviinae. 



Erato occurs fossilized in the miocene and pliocene deposits 

 of Europe and America, and a single species has been reported 

 from the eocene of Texas : species have been recently charac- 

 terized from the eocene and miocene of South Australia and 

 Tasmania. 



Tijpirnl or Smooth /S/wr/Vx. 



K. L. \CUKVMA, Gray. PI. 4. figs. :}-2, :\-. 



Whitish, the lip faintly roseate, usually obscurely three-banded 

 with rose-color. Length, 5 mill. 



Jnpftn (Dr. Siebold,;. AnttroUn (Gray). 

 E. ntilci.fr.ra, Reeve, non Gray (fig. 37), may be synonymous. 



