CHAPTER II: THE ARGONAUT. PAPER 



NAUTILUS 



Family Argonautid^ 



Genus ARGONAUTA, Linn. 



Shell a flat, roundish spiral, four to eight inches across, 

 unchambered, ship-shaped, with double keel; ornamented with 

 knobs and swollen veins ; thin, porcellanous, whitish, tinged with 

 yellow: secreted by broad ends of dorsal arms, and held by them; 

 not a true shell but an egg cradle; no muscular attachment. 

 Male about one inch long, destitute of shell, third arm on left 

 side hectocotylised, becoming detached and left in mantle of 

 female at breeding time. Female large, with eight arms; suckers 

 stalked. Distribution, all tropical oceans, and extending to 

 latitude forty degrees north and south. Shells much in demand 

 among collectors. Five species. 



The Argonaut or Paper Nautilus (A. Argo, Linn.), has 

 the characteristics of the genus, and is the best known species. 

 Diameter, 6 to 12 inches. 



Habitat. — ^Tropical and warm seas. 



The two cephalopod mollusks with external shells were ob- 

 served centuries ago sailing about in their graceful boats, and 

 each was called Nautilus, which means "little sailor." One has 

 a pearly shell; the other a white one, thin as paper. So one was 

 called the Pearly Nautilus, the other the Paper Nautilus. 



The pearly one was rarely seen. But as summer came on, 

 fleets of the paper nautili appeared off the Mediterranean coasts. 

 Writers of Greece and Rome called them Argonauta, an allusion 

 to the fabled Argonauts, who, under Jason, sailed away to find 

 the Golden Fleece. 



Now, is n't it strange that a large and conspicuous mollusk 

 like Argonauta, sailing all warm seas, appearing by hundreds 

 close to shore where men could pick it up and make its acquain- 

 tance, should have kept the secrets of its ways of life so long 



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