266 MOLLUSCA. 



OLIVA, Brug., 



So named from the oblong and elliptical shape of the shell, the aperture 

 of which is narrow, long and emarginated opposite to the spire, which is 

 short; the plica of the columella are numerous, and resemble stria; the 

 whorls are sulciform. These shells are quite as beautiful as the Cypraa. 



The animal has a large foot, the anterior part of which (before the head) 

 is separated by an incision on each side; its tentacula are slender, and the 

 eyes are on their side k about the middle of their length. The proboscis 

 and siphon are tolerably long; but it has no operculum. 



The remainder of the genus Voluta was afterwards divided into five, by 

 M. de Lamarck. They are VOLVARIA, VOLUTA, MARGINELLA, MITHA and 

 CANCELLARIA. 



BUCCINUM, Lin. 



This genus comprises all the shells furnished with an emargination or a 

 short canal inflected to the left, and in which the columella is destitute of 

 plica. 



Brugieres has divided them into the four genera of Buctinum y Purpura, 

 Cassis, and Terebra, part of which have been again subdivided by Messrs 

 de Lamarck and Montfort. The 



BUCCIKUM, Brag. 



Includes the emarginated shells without any canal, whose general form, 

 as well as that of the aperture, is oval. The animals, all such as are known, 

 are deprived of the veil on the head, but are furnished with a proboscis, two 

 separated tentacula, on the external side of which are the eyes, and a horny 

 operculum. Their siphon extends out of the shell. 



NASSA, Lam. 



The side of the columella is covered by a more or less broad and thick 

 plate, and the emargination is deep, but without a canal. The animal re- 

 sembles that of a true Buccinum, and there are gradual transitions among 

 the shells, from one subgenus to the other. 



EBTJRNA, Lam. 



A smooth shell without a plicated margin, and a widely and deeply um- 

 bilicated columella. The general form of their shell is closely allied to that 

 of the Oliva. Their animal is unknown. 



ASTCILLAIITA, Lam. 



The same smooth shell, and at the lower part of the columella a marked 

 lip; there is no umbilicus, neither is the spire sulcated. The animal of 

 several species resembles that of the Oliva, the foot being still more de- 

 veloped. 



