gasteropoda PULMONEA. 27 
their branchiae are attached under the margin of their mantle, as in 
the Inferobranchiata(a), 
ORDER L 
PULMONEA*. 
The Pulmonia are distinguished fromtlie otlier Molluscaby respiring 
elastic air through a hole opening under the margin of the mantle, 
and which they dilate and contract at will ; and accordingly have no 
* M. de Blainville prefers the term Puhnonobrunchiata. 
(a) The Gasteropodes form, in Lamarck’s classification, the Second Order 
of his 
TWELFTH CLASS. 
Mollusca. 
Order II. — Les Gasteropodes, 
Animals with the body straight, never in a spiral form, nor enveloped in a shell 
capable of containing the whole of it ; they have beneath the belly a foot or muscular 
disk, united nearly to the whole length of the body, and serving them to crawl with. 
Some are naked, others are screened by a dorsal shell, not sheathed in the body ; 
and others again, have a shell more or less concealed in their mantle. 
First Section . — Les Hpdrobranchia. 
Genus Glaucus . . . 
... 1 
.... Eolis 
.... Tritonia . . . 
... i 
. . . . Scyllaea . . . 
.... Tethys . . . 
. . . . Doris 
Phyllidia . 
Chiton ellus 
Chiton . . . 
Patella . . . 
Pleurobranchus 
Umbrella. . . . . 
Parmophora 
Emarginula 
Fissurella 
Pileopsis 
Calyptraea 
Crepidula 
Ancylus . . 
•} 
Acera . , 
Bullaca 
Bulla . . 
■< 
L 
Animals only breathing water. 
("The respiratory organs, in what- 
ever part they are situated, 
are always elevated, either 
in filets, laminije, tufts, or 
like a comb ; they are placed 
I above the mantle, either on 
the back or on the sides, and 
L not in any particular cavity, 
p Respiratory organs placed be- 
I neath the border or edge 
I of the mantle, and disposed 
in a longitudinal series round 
I the body, or on one side, not 
being placed in any particular 
cavity. 
{ Gills as above, but placed on 
the right side of the body 
only. 
p Respiratory organs placed in a 
[ cavity appropriated to them 
I on the back of the animal, 
I near the neck, projecting 
\ either within the cavity or 
I above it. Shell always exter- 
nal and covei'ing the animal, 
L which is without tcntacula:. 
■Gills placed in a particular ca- 
vity near the posterior part 
of the back, and covered by 
the mantle or by an opercu. 
lary shield. — No tentaculse. 
First Family. 
Les Tritoniens. 
Second Family. 
Les Phyllidiens. 
Third Family. 
Les Semiphyllidiens. 
Fourth Family. 
Les Calyptraciens. 
Fifth Family. 
Bull^ens. 
