280 American Seashells 



Family RETUSIDAE 

 Genus Retusa Brown 1827 



Retusa obtusa Montagu Arctic Barrel-bubble 



Figure 59a 



Arctic Seas to off North Carolina. 



3 mm. in length, fairly fragile, smooth, stubby and with the spire com- 

 monly slightly sunk or only a little elevated. Columella smooth. A chink- 

 like umbilicus is present. Color translucent-white with yellowish brown stain- 

 ing. Common from shore to 90 fathoms. R. pertejiuis Mighels and R. 

 turrita Moller are this species. 



Retusa sulcata Orbigny Sulcate Barrel-bubble 



North Carolina to southeast Florida and the West Indies. 



2 mm. in length. Characterized by its small size, fine axial threads, 

 white color, oblong shape, flat sides and deeply sunken spire. Moderately 

 common from 3 to 95 fathoms. 



Retusa canaliculata Say Channeled Barrel-bubble 



Plate 26X 



Nova Scotia to Florida, Texas and the West Indies. 



4 to 6 mm. in length, solid, oblong with its spire moderately elevated, 

 but almost invariably eroded. Glossy smooth, except for microscopic growth 

 lines. Outer lip thin, advanced above. Columella of a single, raised, strong 

 spiral ridge. Suture slightly channeled. Nucleus (when present) very small 

 and pimple-like. Color white to cream, commonly with dark, rust-brown 

 staining. Acteocina candei Orbigny is probably only a southern representa- 

 tive of this species. A common shallow-water species which was formerly 

 placed in the genus Acteocina. 



Genus Pyrunculus Pilsbry 1894 

 Pyrunculus caelatus Bush Bush's Barrel-bubble 



Plate 26W 



North Carohna to southeast Florida. 



3 mm. in length, pyriform in shape, rather thick and opaque-white. 

 Spire concealed within a very deep pit. Rather rare from 15 to 43 fathoms. 



Genus Rhizorus Montfort iSio 

 {Volvula A. Adams, not Gistel) 



Rhizorus oxytatus Bush Southern Spindle-bubble 



North Carolina to southeast Florida and Cuba. 



