190 Afnerican Seashells 



Lunatia pallida Broderip and Sowerby Pale Northern Moon-shell 



Figure 43c 



Arctic Seas to off North Carolina. Arctic Seas to California. 



1% to 1% inches in length, not quite so wide, smooth, pure-white in 

 color, and covered with a thin, yellowish white periostracum. Parietal wall 

 moderately thickened with a white glaze. Umbilicus almost closed to slischtlv 

 open. Commonly dredged offshore in cold northern waters. In the Atlantic, 

 this species rarely exceeds i inch in length. P. groenlandica Moller may be 

 this species. 



Subfamily SININAE 

 Genus Sinum Roding 1798 



Sinum perspectivum Say Common Baby's Ear 



Plate 22s 

 Virginia to Florida and the Gulf States. The West Indies. 



I to 2 inches in maximum diameter, but very flat, with very large white 

 aperture and strongly curved columella. Numerous fine spiral lines on top of 

 whorls. Color dull-white with a light-brown, thin periostracum. Animal 

 envelops the shell. Commonly found in shallow, sandy areas, especially in 

 the Carolinas and the west coast of Florida. 



Sinum maculatum Say Maculated Baby's Ear 



Carolinas and west coast of Florida. 



Similar to perspectivum, but shell not so flat, with weaker spiral sculp- 

 ture, and colored dull-brown or with yellowish brown maculations. 



Sinum scopulosum Conrad Western Baby's Ear 



Monterey to Todos Santos Bay, Lower California. 



I to 1/4 inches in length, 4 whorls, the early ones being very smooth, 

 the last whorl very large. Numerous spiral grooves can be seen with the 

 naked eye. Shell chalky-white, but usually covered with a thin, yellowish, 

 translucent periostracum. The spire is more elevated and the whorls more 

 inflated than those in S. debile Gould, from Catalina Island to the Gulf of 

 California. S. scopulosum is moderately common, and is the same as S. cali- 

 fornicum Oldroyd. 



