440 American Se ash 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 



Plate 3od 



Cape Cod to south Florida and the Gulf States. 



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 periostra- 

 cum 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 



Plate 30g 



Cape Cod to south Florida, the Gulf States and the Caribbean. 



I to I /4 inches in length, elongate, subcylindrical, fragile and smooth. 

 The valves are reinforced internally by a very weak, radial rib (commonly 



