The Moon Shells and Velvet Shells 



The Western Moon Shell (N. Lewisii, Gld.) is the largest 

 species known. The shell is lighter and thinner than in N. heros. 

 Faint spiral striations are seen on the whorls; the body whorl 

 has an angular shoulder. The outside is yellowish white, the 

 lining polished and stained brown. A callus lobe narrows the 

 mouth of the deep umbilicus. This "snail of prey" has the 

 same predatory habits as its counterpart of the east coast. 

 Diameter, 3 to 5 inches. 



Habitat. — California to Alaska, Japan. 



N. duplicata, Say, has a flatter spire and a smoother shell 

 thsLn N. her OS, with bluish tinge on the pale brownish upper surface. 

 The distinguishing feature is a thick brown lobe that extends 

 over the wide umbilicus, but does not quite close it. The spiral 

 umbilicus is also distinctive. The sand collar is ruffled on its 

 outer border. This species reaches but three inches in diam- 

 eter. It has the same habit as N. heros, and a much wider 

 range. 



Habitat. — New England to Florida, Gulf of Mexico. 



N. clausa, Brod. and Sby., is a whitish moon shell, ^ inch to 

 2 inches across, which has the small umbilicus entirely filled by a 

 callus. The operculum is calcareous, bluish white. It is found 

 in cold seas and at considerable depths. 



Habitat. — Greenland to Massachusetts. 



N. Recluziana, Desh., has a more conical shell than the 

 eastern species, in fact is rather a turban shell in form, and very 

 thick and heavy, with brown banded whorls shading to pale ash 

 colour. It is about 2 to 3 inches long. The umbilicus is 

 closed by a very thick enamel callus. The "sand collar," 

 shaped like a horse's hoof, often has rows of the eggs of Nassa 

 along the top. 



Habitat. — Southern California. 



N. canrena, Linn., is a Floridian and West Indian moon 

 shell found also along the Atlantic to Cape Hatteras. The shell 

 has spiral chestnut bars streaked diagonally with purple on a 

 whitish ground. The base is not coloured. The wide aperture 

 is purple-lined. The umbilicus is partially plugged with a callus. 

 The operculum is calcareous. This is one of the small Naticas, 

 being i to i^ inches in diameter. 



Some tropical moon shells are highly polished and brilliantly 

 coloured. The Philippines furnish several of these, the "zebra," 



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