MOLLUSCA OF PORTO RICO. 
421 
Family TRIVIID4}. 
Genus TRIVIA Gray, 1832. 
Shell generally small, oval or obcvate, inflated, enrolled, transversely grooved and ridged above 
and below, with a longitudinal dorsal furrow, scarcely shining; aperture long, narrow, scarcely 
canaliculate above or below. Anatomy very distinct from that of Cypriea. 
Trivia pediculus Linnaeus. 
Cyprxa pediculus Linnaeus, Syst. Nat., ed. x,p. 724, 1758. 
Cyprxa pediculus Reeve, Conch. Icon., hi, pi. xxm, fig. 181, 1846. 
Shell rather solid, obovate, inflated, with a deep, straight, longitudinal, dorsal furrow, from which 
strong, subradial ridges run over the shell and extend into the aperture; these are subnodulous at 
the dorsal furrow; inner and outer lips thickened somewhat around the base; the space between the 
ridges above and below is faintly wrinkled and nodulous. Color purplish brown, with a dark spot at 
each end of the dorsal furrow and another on each side of it at the middle; these spots vary much in 
shape; the base is smoky tinted. 
Length, 15; diameter, 11 mm. 
Aguadilla, Porto Rico, several fine shells; West Indies; Florida. 
Trivia quadripunctata Gray. 
Trivia quadripunctata Gray, Zool. Journ., in, p. 368, 1827. 
Cypriea quadripunctata Reeve, Conch. Icon., nr, pi. xxv, fig. 146, 1846. 
Shell small, obovate, slightly elongated; dorsal groove well marked; transverse ridges fine, 
slightly nodulous near the groove, with numerous intermediate ones which only reach part way up 
the back; outer lip thickened. Color purplish pink, often tinted darker on the extremities; on each 
side of the dorsal groove there are two darker spots, and these four spots form a zigzag row. 
Length, 8; diameter, 5 mm. 
Aguadilla, Porto Rico, one shell. 
Trivia quadripunctata var. rotunda lviener. 
Cypriea rotunda Kiener, Coq. Viv., p. 141, pi. LIU, fig. 2. 
More globose than the type. Mayaguez, Porto Rico, two shells. 
Genus ERATO Risso, 1826. 
Shell small, subpyriform or suboval, polished; spire always visible, conical; last whorl large; 
aperture nearly straight, narrow, nearly as long as the shell; outer lip thick, thicker in the middle, 
toothed within; columellar area sometimes toothed or plicate; base notched. 
Erato maugeriae Gray. 
Erato maugerix Gray, in Sowerby, Conch. Illustr., p. 17, pi. vii, fig. 47, 1832. 
Erato maugerix Tryon, Man., v, p. 9, pi. IV, figs. 42, 43, 1883. 
Shell small, pyriform, with a moderate spire and flattened whorls; aperture narrow, long, nearly 
straight, and not spread below; the lip much thickened, slightly ascending the spire and heaviest in 
the middle, faintly toothed within; columellar area smooth, feebly plicate at base; canal somewhat 
drawn out, truncate. Color gray or livid, often tinted green, the lip whitish. 
Length, 5; diameter, 3.5 mm. 
Mayaguez, Porto Rico, two worn shells; West Indies; Florida. 
Family STROMBM. 
Subfamily STROM BIN AS. 
Genus STROMBUS Linnaeus, 1758. 
Shell ovoid, smooth, tuberculous or spinous, imperforate, solid, covered with an epidermis; spire 
with numerous whorls, elevated; aperture long, with a notch at the base and one on the outer lip 
above the base, somewhat canaliculate above; lip thickened, dilated; columellar border simple, 
enameled; operculum unguiculate, its edge roughened or toothed. 
