798 DIVISIONS OF THE GASTROPODA. 



in front, with a wide notch, a plaited columella, and a thickened 

 outer lip. The genus is Tertiary and Recent. 



Family 47. Harpid^e. — The type of this family is the genus 

 Harpa, in which the shell is ventricose, with a short spire and a 

 large body-whorl ; the whorls are convex and adorned with transverse 

 ribs, and the aperture is large and notched in front The genus 

 comprises marine types, and is confined to the Tertiary and Recent 

 periods. 



Family 48. Olivid^e. — In this family the shell is elongated and 

 solid, with a narrow aperture, a sharp smooth outer lip, and a callous 

 columellar lip. The members of this family are marine, and are 

 essentially inhabitants of warm seas. 



The "Olives" {Oliva) and " Rice-shells" {Olivella) are character- 

 ised by their cylindrical polished 

 shell (fig. 7 1 1, a), with a short spire, 

 a long narrow aperture, notched 

 in front, and an obliquely striated 

 columella. The living Olives are 

 tropical and subtropical in their 

 distribution. A single species of 

 Olivella has been detected in the 

 Cretaceous rocks of California, 

 but with this exception, the Olives 

 are wholly Tertiary and Recent. 



Fig. 711.— a, Oliva Branderi, Eocene; J / . 



b, Ancillaria glatiditta, Eocene. 1 he genUS AflClUaria (tig. 7 I I, 



b) is nearly related to Oliva, but 

 the spire is produced, and is covered with shining enamel. Species 

 of Ancillaria occur in the Upper Cretaceous rocks, but the genus is 

 mainly Tertiary and Recent. 



Family 49. Cancellariid^e. — The type of this family is the 

 genus Cancellaria, in which the shell is oval or turreted, with a large 

 body-whorl ; and the aperture notched or canaliculated in front. The 

 columella is obliquely plaited, and the surface is cancellated. The 

 genus ranges from the Chalk to the present day. 



Family 50. Conid^e. — In this family the shell is inversely coni- 

 cal, with a very short spire and an elongated body-whorl. The 

 aperture is long and narrow, notched in front, the columellar lip 

 not plaited, and the outer lip smooth and often notched at or 

 near the suture. The members of this family are all marine, and 

 they are principally Tertiary and Recent, the oldest types being 

 Cretaceous. 



The principal genus of this family is Conus itself, using this 

 name in a comprehensive sense. The " Cones " are distinguished 

 by their short spire and regularly conical shell (fig. 712). Very 

 numerous recent species of Conns are known, and also a consider- 



