108 Marine Shells of the Western Coast of Florida 



slit, 1.5 mm. Shell chalky white, oblong, width less than half the 

 length; apex small, near the posterior end; anal hole about halfway 

 up anterior convex slope; anal fasciole shallow, extending from the 

 perforation to the apex; sculpture of radial ribs and concentric 

 threads; interior glossy, margin slightly crenulated. 



Family TROCHIDAE 



The iridescent nacre which enters so largely into the compo- 

 sition of trochid shells gives them status among the "elegant 

 families". In many species, a dark periostracum conceals the in- 

 trinsic beauty of their lustre from without, but the pearly lining of 

 the interior is always evident. 



The animals are more or less brightly colored in shades of red 

 or terracotta. The head bears two tentacles and between them are 

 two curiously flattened palmettes; a thick fold along each side of 

 the foot gives attachment to a number of tendril-like processes which 

 are always in motion when the creature is active and create an im- 

 pression of delicacy and daintiness. These herbivorous mollusks are 

 often found among seaweeds. 



The shells are variable in shape, some are regularly conic or 

 pyramidal, some turbinate, and some heliciform. The shape of the 

 aperture is also variable. The operculum is corneus, round, multi- 

 spiral, with a central nucleus. 



The many genera of this group are widely distributed through 

 all warm seas, most abundantly in the littoral region though some 

 have been dredged from considerable depths. 



Genus CALLI0ST03IA Swainson, 1840 

 Calliostoina eugljptami'-G (a. Adams) PI. 21, fig. 138 



Alt., 21; width of base, 20 mm. Shell conical, imperforate; rosy 

 brown with darker and lighter flammules and patches usually based 

 on sutural lines; apex dark red, a dark marking outlines apical whorls; 

 spire rather evenly conic; four or five whorls; shoulders of lower 

 whorls rounded; sutures slightly incised; base nearly flat; sculpture 

 of finely beaded spiral lirations, alternately larger and smaller; the 

 penultimate whorl bears from seven to ten and the base from ten 



^^^ Gr., kalos, beauty; stoma, mouth; eu, well; glyph fin, to carve. 



