OUVKLLA. (>: 



A number of fossil species have been described; they com- 

 mence in the Eocene period. 



The mantle of the Olive is small, its edges applied to the 

 margin of the aperture, and terminating in a posterior filament 

 which, coiling in the channeled suture of the spire, appears to 

 be useful in keeping the mantle in place. The sides of the foot 

 are wide and reflected more or less on each side over the back 

 of the shell. As in some other mollusks having similarly formed 

 shells, the animal possesses the power of absorbing away the 

 earlier volutions in order to make space for its growth ; it also 

 protects the at first very thin embryonal whorls by internal cal- 

 cification, so that the extreme tip of the spire becomes solid. 



At Mauritius, Olives are fished with a line having three or 

 four strings attached, each baited with pieces of fish. This line 

 is thrown into the sea and allowed to remain until the mollusks 

 have become well settled to their feast, and then drawn in, The 

 Polynesian Islanders use the smaller species extensively for the 

 manufacture of ornaments such as bracelets, girdles, etc., 

 piercing them at the spire and then stringing them. They 

 prefer pure white shells for this purpose, and cause the colored 

 markings to disappear by application of heat. Mr. John Brazier, 

 of Sydney, New South Wales, has recently sent me specimens of 

 the beautiful 0. Australia, thus treated by the natives of New 

 Guinea they might readily be mistaken for a distinct species. 



OliveUa biplicata, Sby., appears to have been used as money 

 by the Californian Indians, under the name of col-col, and is 

 still manufactured into necklaces by them.* 



. Genus OLIVELLA, Swa'nson. 



Olivella is distinguished from Oliva by the small size of its 

 shell and more produced spire, by the presence of a large, thin, 

 horny operculum, and the want of eyes. Dr. Paul Fischer has 

 recently attempted to show that another distinction arises from 

 the absorption of the internal whorls of the shell, in the Olivella, 

 as in Auricula, this absorption not taking place in the typical 

 Olives ; however, in 0. reticularis I have found the interior walls 

 absorbed away so that very little of their substance remains, 



* Steams, Am. Natuialist, xi, 344. 



