CHAPTER XIII. 
PULMONARY GASTEBOPODS. 
‘ Escargot, escargot, 
Montre-moi tea cornes.’ 
'We Lave said, live in the air and breathe the natural atmosphere, 
respiratory organ is a cavity in the walls of which the blood- 
vessels form a complicated network. The air enters this cavity 
^ l0ll gh an orifice, which the animal opens and shuts at will — a species 
0 bing, in short, which is placed upon the hack of the animal. They 
a|(i both terrestrial and aquatic animals. In the latter case, they must 
t0 ’ Ue to the surface of the water in order to breathe, like the phoeas 
dolphins among the Mammifera. The terrestrial species compre- 
6tl d two families : the Suails (Helix) and the Slugs (Limax). The 
l Tiatic species comprehend the single family of Lin 
ItJ5 Pulmonary Gasteropoda comprehend those molluscs which, 
It 
imnm. 
is only necessary to witness the snail as it creeps along the 
^Vel walks of a garden, or in the damp alleys of a park, in order to 
ee that it is a being of higher organization than the molluscs, for the 
>,,, Part stationary, with which we have hitherto occupied ourselves. 
e Edible Snail (Helix aspersa) goes and comes; it roams and 
inters after its own peculiar manner, searching for its food or its 
ea sure ; it has a head and two prominent tentacles, which feel and 
teta to express their sensations ; it has nerves, a brain, a strong 
^° u Ih, and a well-formed stomach. It is, in short, a complete being ; 
Remains to us a sort of resting-place after the obscure existences — 
e °htuse creatures which we have just passed in review. 
