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440 American Seash ells
2 inches in length, moderately inflated. Sculpture of numerous, coarse,
irregularly sized, radial threads. Color variable and brighter on the inside:
whitish, yellow, or stained with red, rose or purple. Beaks inflated and rolled
in under themselves a little. A moderately common, intertidal species, also
known from the Indo-Pacific.
Genus Tagelus Gray 1847
Tagelns plebehis Solander Stout Tagelus
Cape Cod to south Florida and the Gulf States.
Plate 3od
2 to 3^4 inches in length, oblong, subcylindrical, rather inflated, rounded
posteriorly, obliquely truncate anteriorly. Beaks indistinct, close together and
nearer the posterior end of the shell. Hinge with 2 small, projecting cardinal
teeth, with a large bulbous callus just behind them. Exterior smoothish, with
tiny, irregular, concentric scratches. Periostracum moderately thick, shiny,
olive-green to brownish yellow. Moderately common in shallow water in
mud-sand intertidal areas. T. gibbiis Spengler is a later name for this species.
Tagelus calijornianus Conrad Californian Tagelus
M onterey, California, to Panama.
Plate 29U
2 to 4 inches in length. Pallial sinus does not extend past a line vertical
to the beaks. External color yellowish white under a dark-brown periostracum
which is radially striated. Interior white. Common on muddy sand flats
near marshes. Lives 8 to 10 inches below the surface of the sand.
Tagelus affinis C. B. Adams Affinis Tagelus
Southern California to Panama.
1/4 to 2% inches in length. Shell thin. PalHal sinus extends to a line
shghtly beyond tlie beaks, that is, about 53 to 60 percent of the total length
of the shell. Dredged from 3 to 40 fathoms in mud-sand, but commonly
washed ashore.
Subgenus Mesopleura Conrad 1867
Tagelus divisus Spengler Purplish Tagelus
Cape Cod to south Florida, the Gulf States and the Caribbean.
Plate 30g
I to I /4 inches in length, elongate, subcylindrical, fragile and smooth.
The valves are reinforced internally by a very weak, radial rib (commonly