86 THE HALL OF SHELLS. 
times a foot across, delicately porcelainlike, of 
a light-buff tint, beautifully veined or striped 
in a zlgzag pattern with chestnut brown. The 
beauty of the nacreous lining of this shell I 
have no words to describe. It seems a min- 
eling of the delicate tints of most delicate 
flowers and the beauty and brilliancy of rarest 
gems. 
“The shell is divided into chambers, hence 
the name ‘chambered nautilus.’ When very 
young this is not the case, but as the animal 
increases in size it leaves its first compartment, 
which becomes an empty chamber, and moves 
forward to one still larger; the rim of the shell 
continues to grow, and back of the little oceu- 
pant a pearly partition is produced. This is 
repeated from time to time, the little animal 
always using the room next to the vestibule; 
but through all preserving a connection by 
means of a silvery membranous tube called a 
siphuncle. 
“ But few species of these animals now re- 
main and they alone in warm seas, but geology 
shows that both Argonauta and Nautili were 
very abundant in earlier periods. 
“The fossil ammonite was a kind of ‘old- 
fashioned cousin’ to the nautilus or paper 
sailor. These are found in great abundance, 
