MORPHOLOGY OF ANIMALS 



m- 



ac .h .p 



aa 



Fig. 13. Respiratory and Circulatory Organs of Snail and Crayfish. A, Snail (Paludina) ; a, 

 auricle; v, ventricle of heart; aa, abdominal aorta; ac, cephalic aorta; k, kidney; /, liver; 

 g, gills ; V, vein carrying blood from body to gills ; bv, branchial vein carrying blood from 

 gills to heart (blood goes from heart to all parts of body, comes back to kidney and gills 

 and then goes to heart); t, tentacles; m, mouth; eg, cerebral ganglion with eye on its 

 anterior side ; pg, pedal ganglion with statocyst on its posterior side ; /, foot. (After Leydig). 



B, Crayfish ; h, heart with 3 ostia (openings) on each side into pericardium (/>) ; aa, ab- 

 dominal aorta ; ac, cephalic aorta ; as, sternal artery. Arteries are shown as empty tubes, 

 veins and sinuses as black. Blood goes out from heart to all parts of body, comes back 

 through veins and sinuses to gills, and then goes to the pericardium and heart. (After Claus), 



