70 UNIVALVES. NAUTILUS. 



NAUTILUS.— Pearly Sailor. 



Animal— (vide Rumpf. Mus. tab. 17./</. B.) Shell uni- 

 valve, divided into several departmentSf communicating 

 with each other by an aperture. 



This genus contains no less than thirty-one species. 

 They are nearly allied in point of general formation and 

 structure; but the most prominent mark of distinction is, 

 that most of the species have their whorls divided into 

 separate compartments or chambers, which are connected 

 by a little tube or pipe (syphon), which runs spirally 

 throughout the shell. This syplion is sometimes central 

 in the shell, and sometimes contiguous to the surface. 



The Nautilus Pompilius, when bisected, exhibits in an 

 eminent degree the pearly comcamerations for which this 

 genus is famous. The inhabitants of the East often con- 

 vert fine specimens of the above species into drinking cups, 

 whose snrface they carve into various devices and orna- 

 ments; they also frequently remove the outer coating en- 

 tirely, and thereby bring the shell to a beautiful pearly 

 mass. The umbilicated varieties of this species are ac- 

 counted exceedingly scarce. 



The genera] form of tiie Nautili is mostly spiral or 

 scroll-like, some having their whorls contiguous, as the 

 Pompilius, calcar, crjspus, &c. and others having them 

 detached or separated, as the spirula, &c. But others, 

 again, have a very different formation, being tooth or 

 funnel-shaped, almost like some of the Dentalia ; such 

 arc Ihe fascia, legumcn, obliquus, <kv. 



The size of the Nautili difTcrs exceedingly; some are 

 so small as only to be defined by the microscope, while 



