23 a 
1i6 CLASS IX. ORDER IV. 
8g 
out teeth, the valves united into one. acre, — 
yielding byssus of which silk is sometimes made. 
ORDER 4. UNIVALVA. 
Soft animals, having shells with single valves. 
ARGONAUTA, (paper nautilus,) animal a sepia 
or Clio; shell univalve, spiral, involute, membra- 
naceous, one-celled. 
Navuritus, (pearl nautilus,) animal sepla ; 
shell univalve, divided into several departments 
communicating with each other by an aperture or 
siphunculus. 
Conus, (cone,) animal iieaee: shell univaive. 
convolute, turbinate ; aperture efi. longitudi- 
nal, linear, without teeth, entire at the base; pil- 
lar smooth. 
Cyprara, (gourie, sea-porcelain,) animal a li- 
max ; shell univalve, invelute, suboyate, smooth, 
obtuse at each end; aperture effuse at each end, 
linear, extending the whele length of the shell, 
and toothed each side: 
Buwia, (dipper- shell,) animal a limax; shell 
univalve, convoiute, unarmed vith teeth; aper- 
ture a little enaiiened; oblong, lon citudiiel, very 
entire at the base; pillar-lip oblique, smooth. 
Voiura, (mitre, volute,) animal limax 5 shell 
one-celled spiral; aperture without a beak, and 
somewhat cffuse ; pillar twisted or plaited, gene- 
rally without lips or perforations. 
Buccinum, (whelk, helmet-shell,) animal li- 
max ; shell univalve, spiral, gibbose ; aperture 
: ovate, terminating in’ a short canal leaning to the 
right, with a retuse beak or projection ; pillar-lip 
expanded. 
