COLUMBELLA. 103 



ALCIRA, H. Adams. Shell fusiform, thin, spire produced ; whorls trans- 

 versely striated ; aperture ovate ; colurnella truncate, with a single 

 oblique fold anteriorly; outer lip thin, smooth internally, posteriorly 

 expanded, and with the anterior margin crenulated. Differs from the 

 other groups in its expanded lip, which is not thickened, and from most 

 others in the columellar fold. 



ENGINA, Gray. Shell ovate-conic ; spire sharp ; with longitudinal 

 nodulous ribs, decussated by revolving lines or riblets ; aperture narrow, 

 with several oblique plications in front ; outer lip thickened, internally 

 toothed, gibbous and grooved posteriorly. Dentition, Manual, iii, 

 t. 27, f 36. 



PUSIOSTOMA, Swainson. Shell ovate ; inner lip convex between the 

 granular teeth ; outer lip internally greatly thickened and toothed in 

 the middle. 



COLUMBELLINA, d'Orb. Shell Strombiform, oval, thick, ventricose, 

 ribbed; aperture narrow, flexuous, narrowed in the middle, ending 

 posteriorly in a prolonged lateral canal ; outer lip much thickened and 

 smooth within. (Mostly fossil.) G. ornata, d'Orb. (PI. 42, f. 3). Cre- 

 taceous, France. 



COLUMBELLAIUA, Rolle. Shell long-oval, Buccioiform, body-whorl 

 rather infhved, spire moderate ; surface nodulous, caused by decussating 

 sculpture ; aperture wide below ; outer lip rounded, not inflected in the 

 middle, with strong revolving ribs within ; columellar callus thin, 

 showing the sculpture of the body-whorl. C. corallina, Quenst. (PI. 

 42, fig. 4). U. Jura, Europe. 



AMPHISSA, H. and A. Adams. Shell Bucciniform, longitudinally ribbed; 

 spire elevated ; aperture rather wide, enlarging below, and terminating 

 in a wide anterior sinus ; inner lip callous, plicate below : outer lip not 

 thickened on the margin, plicate within. Dentition, PL 42, fig. 2. 



Genus COLUMBELLA, Lamarck. 



These beautiful little mollusks, very numerous in species and 

 in individuals, are widely distributed, occurring in all parts of 

 the world, both in cold and torrid climates ; although most 

 numerous in tropical waters. They are found crawling on the 

 surface of sand-flats in shallow water, or living on stony 

 beaches, where they sometimes congregate about and under 

 stones in considerable numbers. 



Yery few descriptions of the living animal have been made, 

 and even figures of it are not numerous. 



The few fossil forms of Columbella are comparatively recent, 



