80 UNIVALVES —— ARGONAUTA. 
The color of the shells is mostly blueish, or dingy 
white, but the keel is often tinged with a brownish hue. 
The size of the Argonaute 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 ‘Aoyovavrne a name given 
to the companions of Jason in his expedition to recover 
the golden fleece. 
Division |._—Keel toothed. 
Faminy 1.—Summit interiorly curved. 
Scientific Name. Locality. Common Name. 
ATgo sereeeeeeee Cape of Good Hope: ---- OrientalArgonaut 
Tuberculata ---- South Seas, Brazils----- Tuberculated do 
Hians -+++-+---- China, Red Sea -------- Gaping --- do - 
Gondola -- ----- Mozambique, Mauritius-- Boat ------ do -- 
Haustrum ---- -- East Indies ----- -++ «eee Bucket---- do - 
FamiLy 2.—Summit exteriorly curved. 
Vitrea ....- ersteens Amboyna cu daop odo dDud Brittle -»--- do -- 
Division I].—Keel not toothed. 
Cymbium-:------ Mediterranean ---+--+--+ Minute---- do -- 
Cornu ----+-+--+ Cape of Good Hope ---- Hornshap’d do -- 
Diviston Il.—Umbilicus perforated. 
Arctica «+--+... Greenland ------«-- eco § ArctiC. <2 -.d0 == 
