THE ALIMENTARY CANAL. 
81 
t io. 45—Anatomy of a Gasteropod (Snail): a , mouth ; 6, foot; c, amis; d , lung? 
e, stomach, covered above by the salivary glands ; /, intestine ; g , liver; h , heart; 
i, aorta; j, gastric artery; Z, hepatic artery; k , artery of the foot; m, abdominal 
cavity, supplying the place of a venous sinus; n, irregular canal communicating 
with the abdominal cavity, and carrying the blood to the lung; o, vessel carry¬ 
ing blood from the lung to the heart. 
valve, blit is not so clearly distinguished from the gullet, 
so that regurgitation is easy . 42 Indeed, it is common for 
Pm. 46 _Anatomy of a Lameilibranch (Mactra): a , shell; h, mantle; c, tentacles, or 
Ups; d, mouth; e, nerves; /, muscles; g, anterior, and n, posterior ganglion; h , 
liver; i, heart: k, stomach; Z, intestine passing through the heart; m, kidney; o, 
anal end of the intestine; p , exhaleut, aud q, inhalent respiratory tubes, or si¬ 
phons ; r, gills; s, foot. 
6 
