560 



MOLLUSCA 



FAMILY 6. MITRIDAE. 



Shell smooth and polished, elongate, conical, with a high spire and 

 a small, narrow aperture; columella with folds: several hundred species, 

 in tropical seas. 



MITRA Lamarck. Shell thick; outer lip thick and smooth within: 

 200 species, including many beautiful shells which are used as ornaments. 



M. papalis (L.). Papal mitre. Length 13 cm.; a revolving row of 

 tooth-like folds on the suture; color white, with irregular red spots: 

 Indian Ocean; often used as ornaments. 



M. swainsoni Broderip (Fig. 881). Length 8 cm.; surface with 

 numerous fine revolving stripes: North Carolina and southwards. 



Fig. 881 



Fig. 882 



FAMILY 7. OLIVIDAE. 



Shell brightly colored and polished and elongate, with a short spire 

 sometimes more or less covered by a callous deposit, and a very large 

 lower whorl which makes up the greater part 

 of the shell; aperture long and narrow; oper- 

 culum often wanting : about 250 species, mostly 

 subtropical. 



1. OLIVA Bruguiere. Shell almost cylindric- 

 al; columella with folds; no operculum; foot 

 large, partly enveloping the shell: 150 species. 



O. litterata Lamarck (Fig. 882). Shell 

 slender, tapering towards both ends, 6 cm. 

 long, whitish in color, with spiral bands of 

 brown markings; aperture lined with violet: 

 North Carolina to Key West; West Indies; 

 on sandy beaches. 



2. OLIVELLA Swainson. Shell small; spire taller than in Oliva; 

 suture caniculated; operculum present; tentacles and eyes absent: 31 

 species. 



0. mutica (Say). Rice shell (Fig. 883). Shell fusi- 

 form, 12 mm. long; color whitish, with wavy brown bands 

 on the lower whorl; aperture half the length of the 

 shell: North Carolina to Florida; West Indies; on sandy 

 beaches. 



3. HARPA Lamarck. Harp shell. Shell large, with 

 a large, bulging lower whorl and with prominent longi- 

 tudinal ribs; foot large; radula absent in the adult; aperture large; no 

 operculum : 9 species, in tropical seas, but not in the Atlantic. 



Fig. 881 Hitra swainsoni 



(Dall). Fig. 882 Oliva 



litterata (Rogers). 



Fig. 883 



Olivella 



mutica 



(Rogers). 



