When in our boyhood days we attempted to arrange our shells, we were taught to use the Lamarckian system, that of Linne having been discarded many years previous.

The great reforms in the classification of shells are evidenced by the numerous manuals of conchology based on the works of Lamarck.
We used to hear much of the Lamarckian genera of shells, and Lamarck was the first to perceive the necessity of breaking up into smaller categories the few genera of Linne, which now are regarded as families.
He may be said to have had a wonderfully good eye for genera.

All his generic divisions were at once accepted, since they were based on valid characters.
Though not a comparative anatomist, he at once perceived the value of a knowledge of the internal structure of animals, and made effective use of the discoveries of Cuvier and of his predecessors--in fact, basing his system of classification on the organs of respiration, circulation, and the nervous system.
He intimated that specific characters vary most, and that the peripheral parts of the body, as the shell, outer protective structures, the limbs, mouth-parts, antennae, etc., are first affected by the causes which produce variation, while he distinctly states that it requires a longer time for variations to take place in the internal organs.

On the latter he relied in defining his classes.
One is curious to know how Lamarck viewed the question of species.

This is discussed at length by him in his general essays, which are reproduced farther on in this biography, but his definition of what a species is far surpasses in breadth and terseness, and better satisfies the views now prevailing, than that of any other author.
His definition of a species is as follows: "Every collection of similar individuals, perpetuated by generation in the same condition, so long as the circumstances of their situation do not change enough to produce variations in their habits, character, and form." Lamarck's rare skill, thoroughness, and acuteness as an observer, combined with great breadth of view, were also supplemented by the advantages arising from residence in Paris, and his connection with the Museum of Natural History.