60 Lamarck's Genera of Sheik. 



10. Eburna*. 



Shell oval, or elongated ; right lip very simple. Aperture lon- 

 gitudinal, notched at the base. Columella umbilicated at the 

 upper part, and channelled below the umbilicus. Distinguished 

 from buccinum by the singular position of the umbilicus of the 

 columella, and, especially, by its being produced at the lower part 

 so as to form a canal, which occupies the rest of the left lip. In 

 other respects the eburnee resemble the buccina in their general 

 form, and by the notch at the base of the aperture. Their ex- 

 terior surface is smooth, and polished. 



Type. Eburna glabrataf. (Buccinum glabratura. Linn.) 

 Shell elongated, oval, bisulcated at the base, very smooth, po- 

 lished, pale brownish yellow ; whorls slightly convex, confluent at 

 the upper part; sutures obsolete. American Ocean. PI. v. 

 Fig. 196. 5 Species. 



11. TerebraJ. 



Shell elongated, turrited, very pointed at the summit. Aperture 

 longitudinal, many times shorter than the spire, and notched at 

 the posterior part of the base. Base of the columella twisted, or 

 oblique. 



The very short columella of this shell presents a peculiar cha- 

 racter; in its general form it much resembles the turritella, but is 

 distinguished from that genus by its aperture, and by the notch at 

 the posterior part of the base ; from the eburnse, by not having 

 the channelled umbilicus, and from the buccina, by the small pro- 

 portion which the length of the aperture bears to that of the 

 spire of the shell. 



Type. Terebra maculate \. (Buccinum maculatum. Linn.') 



Shell conico-subulate, thick, heavy, smooth, white, surrounded 

 with rows of bluish brown spots ; towards the base spotted with 

 pale brownish yellow ; whorls rather flattened. Pacific Ocean. 

 PI. v. Fig. 197. 24 Species. 



* From Ebur, ivory. f Smooth. % dn auger. 



§ Spotted. 



