UNIVALVES— TURBO. 149 
TURBO. — Wreatn, or TURBAN-SHELL. 
DESCRIPTION OF PLATE XXVIII. 
Dy. I].--Fam. 6. Fig. 1. T. chrysostomus. 
Dw. III. Fam. 2. Fig. 5. T.muricatus. Drv. V. Fam. 1. Fig. 2. T. scalaris. 
Div. IV. Fig. 4. T. delphinus. Drv. IX. Fig. 3. T. archimedis. 
Shell univalve, spiral, solid; aperture contracted, orbicular, entire. 
THE greater 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 hay-~ 
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 this 
