AMM0N0CERAT1TES.— A fossil. 



TURRILITES.— A fossil. 



BACULITES.— A fossil. 



ARGONAUTA. 



ARGONAUTA ARGO. Linn. 



Mawes Linn, plate \%,fiy. 1,8. 

 Mart. 1, t. 17,/ 157- 

 This genus is universally well known, and its elegant 

 species form a part of every collection, under the trivial 

 name of Paper Nautilus. There are three species : one 

 ( A. argo) with the keel much narrower than in the others, 

 and the pointed tuberculations on either side of it very 

 sharp; the sides of the shell striated transversely, with 

 wrinkles proceeding longitudinally from the spire; the 

 second species (A. tuberculosa) is more convex at the 

 sides, with nodulous elevations, the keel broader, and 

 the points at each side more obtuse. The third species 

 (A. nitida) has the aperture very much dilated. 



