M.de Lamarck has established with as much care as sagacity the genera of shells." Again he says, in noticing the three first volumes: "The great detail into which M.de Lamarck has entered, the new species he has described, renders his work very valuable to naturalists, and renders most desirable its prompt continuation, especially from the knowledge we have of means which this experienced professor possesses to carry to a high degree of perfection the enumeration which he will give us of the shells" (_Oeuvres completes de Buffon_, 1828, t.

31, p.

354).
"His excellences," says Cleland, speaking of Lamarck as a scientific observer, "were width of scope, fertility of ideas, and a preeminent faculty of precise description, arising not only from a singularly terse style, but from a clear insight into both the distinctive features and the resemblance of forms" (_Encyc.

Britannica_, Art.

LAMARCK).
The work, moreover, is remarkable for being the first one to begin with the simplest and to end with the most highly developed forms.
Lamarck's special line of study was the Mollusca.