68 



ZOOLOGY. 



movements of the vessels themselves, by contractions of the 

 principal vessels. Thus the course of the blood is much less 



Fig. 53. Circulatory Apparatus in a Mollusk.* 

 / i a d b 



Fig. 54. Circulatory Apparatus in the Lobster.f 



* Anatomy of the Snail. a, the mouth ; b b, the foot ; c, the anus ; 

 d d, the lung ; e y the stomach, covered above by the salivary glands ; ff, in- 

 testine; g, the liver; h, the heart; i, aorta;./, gastric artery; I, hepatic 

 artery ; k, artery of the foot ; m m, abdominal cavity, supplying the place of 

 a venous sinus ; n n, irregular canal in communication with the abdominal 

 cavity, and carrying the blood to the lung ; o o, vessel carrying the blood 

 from the lung to the heart. 



t a, the heart ; 6, the ophthalmic artery ; c, the antennar artery ; d, the 

 hepatic artery ; e, superior abdominal artery ; ,/, sternal artery ; g y, venous 

 sinuses, receiving the blood coming from various parts of the body, and 

 transmitting it to the respiratory apparatus (the branchiae, h), from whence 

 it returns to the keart by the branchio -cardiac vessels, i. 



