17NIVA.LTZ HIRLILO, OR COCHLIAL 18. Argonauta. Shell spiral, invo lute, membranaceous, and with one cham ber.
19. Nautilus. Divided into many cham bers, by partitions, perforated with pro jecting pipes. • 20. Conus. Convoluted and turbinat. ed shell ; the aperture longitudinal, li near, open at both ends, and without teeth ; the base entire, and the columella smooth.
21. Cyprza. Involuted, sub-ovate, ob tuse, and smooth ; the opening longi tudinal, linear, dentated on each side, and er.ended to both ends of the shell.
22. Bulls. Convoluted, without spire, opening longitudinal, oblong, and con. tracted at the ends, entire at the base ; the columella oblique and smooth.
23. Volute. Unilocular and spiral; the aperture without a tail, and somewhat open at both ends : columella plaited, with no inner or columellar lip, nor um bilicus.
24. Buccinum. Spiral and gibbous ; the aperture oval, terminating in a gut. ter, which, with the cauda, runs out to the right ; the interior lip smooth.
25. Strombus. Spiral, with one side large, the aperture frequently with a di lated outer lip, terminating in a gutter which turns to the left.
26. Murex. Spiral and rough, with membranaceous sutures ; the aperture ending in an entire, straight, or somewhat ascending gutter.
27. Trochus. Spiral, and nearly coni cal; the aperture nearly tetragonal or rounded, contracted transversely above ; the columella oblique.
28. Turbo Spiral and solid ; the aper ture contracted, orbicular, and entire.
29. Helix. Spiral, subdiaphanoua and
fragile ; aperture close at the ends; with. in lunated, or partly circular, as if a seg ment of the circle had been cut off 30. Nerita. Spiral, gibbous, and flat tish below ; the aperture semiorbicular, or semilunar ; the lip of the columella transverse and fiattishly truncated.
31. Haliotis. Ear shaped; the mouth spread open ; the spire lateral and flat tened ; the disk almost always perforated with a row of holes.
32. Patella. Nearly conical, and without a spire.
Dentalium. Tubular, straight, with one chamber, open at both ends.
34. Serpular. Tubular, adhering to other bodies, often intercepted by entire partitions.
35. Teredo. Round, bending, and lodg ed wood.
36. Sabella. Tubular, formed by grains of sand, on a membranous The French naturalists, whose late ex ertions have added much to the funds of this science, have thought it necessary to adopt some changes with respect to the preceding arrangement. These changes would, indeed, derive some support from the high characters which have suggest ed them ; no one having done more of late years to the advancement of this spe cies of knowledge than Brugulere and La marck. Their observations shall there fore be introduced under the several ge nera to which they apply, whilst the or der in which they are taken shall be that of Bose, in " Histoire Naturale des Co quilles."