NATICIDAE 189 



Genus Lunatia Gray 1847 

 Lunatia beros Say Common Northern Moon-shell 



Figure 22a 



Gulf of St. Lawrence to off North Carolina. 



2 to 4% inches in length, not so wide; globular in shape; umbilicus deep, 

 round, not very large, and only slightly covered over by a thickening of the 

 columellar wall. Color dirty-white to brownish gray. Aperture glossy, whit- 

 ish or with tan or purplish brown stains. Periostracum thin, hght yellow- 

 brown. Operculum corneous, light-brown and thin. A very common inter- 

 tidal species in the New England area. The t^^ case is a wide, circular ribbon 

 of sand, about the thickness of an orange peel and easily bent when damp. 

 The tiny eggs are embedded in the ribbon. 



Lunatia triseriata Say Spotted Northern Moon-shell 



Plate 22m 



Gulf of St. Lawrence to North Carolina. 



^ inch in length, similar to young heros but the last whorl usually has 

 three spiral rows of 12 to 14 bluish or reddish brown, squarish spots. The 

 borders of the egg case are crenulated in contrast to the smooth borders of 

 that in heros. This is a moderately deep-water species. Not uncommon from 

 I to 63 fathoms. 



Lunatia groenlandica Moller Greenland Moon-shell 



Plate 22k 



Arctic Seas to off New Jersey. 



% to I inch in length, 4 to 5 well-rounded whorls. Spire about ^ the 

 total length of the shell. Umbilicus very small, mostly covered over by the 

 callus-like swelling of the top of the columella. Suture fine, deeply indented, 

 bordered below by a weakly raised spiral swelling. Shell white, covered by 

 a thin, smooth, greenish-yellow periostracum. Operculum chitinous, trans- 

 lucent, light-tan, paucispiral. Moderately common offshore. 



Lunatia leivisi Gould Lewis' Moon-shell 



Plate 2411 



British Columbia to Lower California. 



3 to 5 inches in length, moderately heavy. Whorls globose, slightly 

 shouldered a little distance below the suture. Umbilicus deep, round and 

 narrow. Characterized by the brown-stained, rather small, button-like callus 

 partially obscuring the top edge of the umbilicus. A very common species 

 found in shallow water to 25 fathoms. They are more commonly found in 

 the summer months. Do not confuse with P. draconis. 



