SEA-HARES. 139 
interior callous lining is beset with firm, horny 
processes, in the form of rhomboidal plates or 
molar teeth, which serve to compress the softened 
vegetable matter transmitted in small portions from 
the first stomach. The third cavity of this com- 
plex apparatus is placed on the left side of the 
body ; its interior surface is studded with sharp, 
horny spines, resembling canine teeth, to pierce and 
SECOND AND THIRD STOMACHS OF SEA-HARE LAID OPEN. 
subdivide the coarse food, and thus prepare it for 
the action of the gastric juice, and other fluids ac- 
cessory to digestion, which enter the stomach from 
adjacent organs. 
The complexity of this structure has reference to 
the coarseness of the materials on which the animal 
subsists—the leathery fronds of the olive sea-weeds, 
which slowly and with difficulty yield their nutri- 
tive elements to the digestive functions. 
The circulation of the blood in these animals 
has been considered, on the high authority of Cu- 
vier, to present extraordinary peculiarities. ‘The 
