UNIVALVES — TURBO. 



149 



TURBO Wreath, or Turban-Shell. 



DESCRIPTION OF PLATE XXVIII. 



Drv. II Fam. 6. Fig. 1. T. chrysostomus. 



Div. III. Fam. 2. Fig. 5. T. muricatus. Div. V. Fam. 1. Fig. 2. T. scalaris. 

 Div. IV. Fig. 4. T. delphinus. Div. IX. Fig. 3. T. archiraedis. 



Shell univalve, spiral, solid ; aperture contracted, orbicular, entire. 



THE gTcater number of the shells of this beautiful 

 genus are solid and ponderous, and many, when decor- 

 ticated, exhibit splendid iridescent colors. They are 

 distinguished from the Trochi by the suborbicular form 

 of the aperture. 



The first division has the pillar margin of the aper- 

 ture dilated, and the pillar imperforate. Among the 

 leading species may be mentioned the T. obtusatus, T. 

 neritoideus, and T. littoreus, or common Periwinkle. 



The next division comprises the solid and imperforat- 

 ed species, of which the most characteristic are the T. 

 petholatus, T. smaragdus, T. chrysostomus, T. pagodus, 

 and T. calcar. The T. marmoratus and T. olearius 

 sometimes attain a considerable size. 



The third division differs from the preceding, in hav- 

 ing the pillar perforated or umbilicated: the T. pica 

 being a common shell, and well known, may be refer- 

 red to as strikingly illustrating the character of thig 



