72 UNIVALVES, NAUTILUS. 



C. — Elongated and nearly straight. 



Semilituus — Semicrozier. Radicula — Bulbous-jointed. 



Lituus — Crazier. Fascia — Banded. 



Obliquus — Obliquely-striated. Inaequalis — Unequal. 



Raphanistrum — Twelve-striated Siphunculus — Piped. 



Raphanus — Seventeen-stria ted. Legumen — Pod. 



Granum — Eight-striated. Orthocera — Carinated. 

 ♦Belemnita — Thunder-bolt. 



CONUS.— Cone. 



Animal — a Limax: Shell univalve, convolute, turbinate; 

 aperture e^use, longitudinal, linear, without teeth, en- 

 tire at the base; pillar smooth. 



Of this beautiful and valuable genus, only seventy-one 

 are described as distinct species; but that number is cer- 

 tainly much less than the real amount. 



The Cones are very similar in form, their principal dif- 

 ferences consisting in the coloring, marking, and band- 

 ing ; yet, form sometimes assists their arrangement into 

 classes: for instance, those which have a subtruncated 

 base, as the C. marmoreus and C. imperialis, constitute 

 one division. Another division is formed of those spe- 

 cies which are pyriform and rounded at the base, and have 

 a thick structure : of these, the C. betulinus and C. glau- 

 cus may be adduced as examples. The C. textile and 

 C. aulicus have a ventricose shape, and are characteristic 

 of the third division: they nearly resemble the C. tulipa, 



