ON MOLLUSCA. 153 
The first work which collected all these recent labours was 
the Natural History of the Mollusca just commenced by 
Denys de Montfort, and executed almost altogether by M. de 
Roissy, a work which constitutes a part of the edition of Buffon 
by Sonnini, and which developed in a suitable manner the 
system of Cuvier. 
In 1809 M. de Lamarck, obliged by his place of Professor 
of the natural history of invertebrated animals, to follow the 
progress of the science, and to put together the new facts 
which it had acquired, proposed a new distribution of those 
animals, in his work entitled Philosophie Zoologique. Divid- 
ing the animal kingdom into six degrees of organization, he 
places in the fourth, ascending from the lowest, and in the 
third, taking an inverse course, the animals with which we 
are now occupied. But he divides them into two classes, one 
to which he leaves the name of mollusca, while to the other 
he gives the new designation of cirrhipoda. In this new 
system, though considerably improved, M. de Lamarck had 
still established some unnatural approximations, and in 1812 
he found it necessary to make some further alterations in his 
general classification of these animals. On this occasion we 
may observe, that in the prodromus of his course M. de 
Lamarck divides the animal kingdom into three primary sec- 
tions, 1. apathetic animals ; 2. sensible animals, (these two 
divisions composing the invertebrata) ; and 3. intelligent or 
vertebrated animals. ‘The philosophic propriety of this divi- 
sion is more than questionable. 
Towards the end of 1814 M. de Blainville published his 
first notions on the methodical arrangement of the malacozo- 
aria, in which he particularly established the necessary rela- 
tion between the shell and the organs of respiration. He also 
drew from this the new character of the symmetry or non- 
symmetry of those organs for the establishment of his orders. 
To carry this history further would be tedious: suffice it to 
