BULLETIN OF ‘ THE UNITED STATES FISH COMMISSION. 
460 
hinge teeth very numerous and even; inside the surface is slightly grooved within the pallial line. 
Color pale brownish, often purple tinted, with wide, wavy, or zigzag, zebra-like stripes of brown. 
Length, 90; height, 40; diameter, 50 mm. 
Mayaguez, many specimens; off Point Melones; Arroyo, Porto Rico. 
Area umbonata Lamarck. 
Area umbonata Lamarck, An. sans Vert., vi, p. 37, 1819. 
Area umbonata Philippi, Abbild., nr, p. 18, pi. xvii, b, fig. 3 a-c, 1847. 
Shell rhomboid, solid, inflated, with a high, sharp posterior ridge and obliquely truncated 
behind; surface in front of the posterior ridge sculptured with rather fine, radiating ribs which are 
crossed by irregular, concentric ridges and rendered subcancellate; behind the posterior ridge are 
about eight stronger, subnodulous ridges; base of shell gaping in front of middle; beaks separated by 
a rather wide, lozenge-shaped area; epidermis blackish, shaggy, standing out in long, striate, leaf-like 
projections on posterior ridge; beak cavities deep. Color purplish brown within and without. 
Length, 50; height, 20; diameter, 20 mm. 
Puerto Real; Boca Prieta; San Juan; Guanica; Mayaguez, Porto Rico. 
Subgenus Bakbatia (Gray) Adams, 1858. 
Area barbata Linnaeus. 
Area barbata Linnaeus, Syst. Nat., ed. X, p. 693, 1758. 
Area barbata Reeve, Coneh. Icon., iv, pi. xiii, fig. 83, 1844. 
Shell subsolid, oblong, or long-rhomboid, generally rounded at each end, moderately inflated, 
slightly gaping below; beaks rather high, situated, one-fourth of the way back from the anterior end 
and separated by a rather narrow ligamental area; surface closely sculptured by various-sized radiating 
ribs, which are crossed by concentric ridges making it cancellated or reticulated, the nodules on the 
ribs often bead-like; posterior ridge low and rounded; epidermis shaggy at the base and posterior end; 
hinge teeth rather few, not strongly developed. Color chestnut, often with lighter clouds, sometimes 
with white rays at the beaks and occasionally one or more of these rays extends to the edge of the shell. 
Length, 50; height, 28; diameter, 17 mm. 
San Geronimo; Guanica; Fajardo, Porto Rico; Ensenada Honda, Culebra; Caballo Blanco Reef, 
Vieques. 
Area Candida Gmelin. 
Area Candida helblingi Chemnitz, vn, p. 195, pl.i.v, fig. 542. 
Area Candida Gmelin, Syst. Nat., p. 3311, 1792. 
Shell thin to solid, rather compressed, subtrapezoidal, gaping at the anterior base; anterior end 
generally truncate; posterior end pointed and obliquely truncate above; beaks high, separated by a 
moderately wide area; surface sculptured with line to rather strong double or single, large or small 
ribs which are heavier on the posterior slope. These are crossed by rude, irregular growth lines and 
ridges, causing the surface to appear somewhat cancellated and beaded; epidermis heavy, shaggy; 
teeth feebly developed. Color white. 
Length, 60; height, 35; diameter, 28 mm. 
Puerto Real; reefs at Ponce; Mayaguez; San Juan Harbor, Porto Rico. , 
Area reticulata Gmelin. 
Area reticulata, etc., Chemnitz, Conch. Cab., vn, p. 193, pi. i.iv, fig. 540. 
Area reticulata Gmelin, Syst. Nat., p. 3311, 1792. 
Shell small, solid, inflated, subrhomboid, with a well-defined posterior ridge which ends in a 
point at the posterior base; anterior end rounded; beaks full, placed well forward, the area between 
them narrow; sculpture consisting of rather strong, radiating ridges which cross still stronger concentric 
ones, the ridges sometimes scaly, and this is especially the case on the somewhat truncated posterior 
end; hinge rather short; the teeth moderately developed; border of shell denticulate. Color whitish. 
Length, 20; height, II; diameter, 9 mm. 
Reefs at Ponce; Mayaguez; Guanica; San Juan Harbor; Hucares, Porto Rico; Caballo Blanco 
Reef, Vieques. 
