80 UNIVALVES ARGONAUTA. 



The color of the shells is mostly blueish, or clingy 

 white, but the keel is often tinged with a brownish hue. 



The size of the Argonautee differs greatly : the A.argo 

 often attains twelve inches in width ; and the A. cornu 

 and A. arctica seldom exceed four lines in diameter. 



The A. vitrea is the most rare, and one of the most 

 beautiful species of the genus. 



The Mediterranean and Indian seas produce some 

 varieties ; others are from the Cape of Good Hope, and 

 some inhabit the Atlantic, Northern, and Greenland seas. 



Argonauta is derived from Apyovavrrjg a name given 

 to the companions of Jason in his expedition to recover 

 the o'olden fleece. 



Division I. — Keel toothed. 



Family I, Summit interiorly curved. 



Scientific Name. Locality. Common Name. 



Argo Cape of Good Hope Oriental Argonaut 



Tuberculata • • • • South Seas, Brazils Tuberculated do 



Hians China, Red Sea Gaping • • • do • • 



Gondola Mozambique, Mauritius- • Boat do • • 



Haustrum East Indies Bucket do ■ • 



Family 2. — Summit exteriorly curved. 

 Vitrea Ambovna Brittle • • • • do • • 



Division II. — Keel not toothed. 



Cymbium Mediterranean Minute do 



Cornu Cape of Good Hope Horn shap'd do 



Division III. — Umbilicus perforated. 

 Arctica Greenland Arctic • • • • do 



