ON MOLLUSCA. 141 
the classic name of mollusca, whether they were naked or in- 
vested with a shell of one or more pieces. ‘This example was 
imitated by M. de Lamarck and almost all the French naturalists. 
Nevertheless, M. de Lamarck, in the last edition of his inverte- 
brated animals, no longer employs the name of mollusca alto- 
gether in the same manner, and only applies it to a part of the 
mollusca of M. Cuvier, which nearly corresponds to his 
ancient division of the cephalous mollusca. M. Rafinesque, 
some years before, had designated this group under the deno- 
mination of malacosia. 
M. de Blainville proposes the name of malacozoaires for the 
type which contains the true mollusca, and malentozoaires for 
the sub-type formed of the articulated mollusca. 
Aristotle defined his mollusca properly so called, as animals 
which have no blood, the fleshy parts of which are external 
and the solid within ; the reverse of this constitutes his defini- 
tion of the testacea. Pliny, and all the zoologists, at the revi- 
val of letters, have pretty nearly admitted the same definition. 
Adanson understands by the word testacea, or coquillages, 
animals whose body is soft, without any sensible articulation, 
and covered altogether, or in part, with a stony crust, called a 
shell, to which it is attached by one or more muscles. 
This is the definition of Linneus: MoLLuscaA—A. simpli- 
cia, nuda, absque testa, artubus instructa. 'TESTACEA— 
A. simplicia, domo, seepius calcareo, obtecta. 
Bruguiéres, in separating the mollusca from the insects, 
gives them as common characters, the being without bones, 
without stigmata, without feet, or without articulations. He 
distinguishes the mollusca, properly so called, because they 
are naked, from his testacea, which are contained in a shell of 
one or more valves. 
M. Cuvier defines them according to their anatomical 
characters: animals without vertebre or articulated skeleton, 
