go 



SEA FABLES EXPLAINED. 



hydro-dynamic law which governs its mode of self-propulsion 

 when swimming, and possibly in some degree within the 

 control of the animal — the latter is relieved of much of the 

 weight of its shell. When the Nautilus is at the bottom of 

 the sea its movement is like that of a snail crawling along 



FIG. ■^^. — THE PEARLY NAUTILUS [Nautilus pompiUus], AND SECTION OF 



ITS SHELL. After Professor Owen. 



a a, Partitions; b b, chambers; b', the last-formed chamber, in which the 

 animal lives ; c c, the siphuncle ; d, attaching muscle ; e e, the hollow 

 arms ; ff, retractile tentacles ; g, muscular disk, or foot ; //, the eye ; /, 

 position of funnel. 



Upon the ground with its shell above it. The shell, in 

 proportion to the" size of the animal that inhabits it, is a 

 heavy one, and unless it were rendered semi-buoyant, its 

 owner's strength would be severely taxed by the effort to 

 drag it along. By the means indicated this portable 



