532 



Comparative Animal Physiology 



blood out through arteries which reach body tissues by way of blood spaces 

 which are derived from the blastocoel or primary body cavity. The blood, 



I, ^^Osculum 



A. SPONGE 



D ,0 

 D^ D 



Ciliated channel 



Coelenteron 



C. NEMATODE 



Lateral 

 "hearts 



D. OLIGOCHAETE 



Hemocoel 



Ostium 



E. CRUSTACEAN 



Ventricle 



Auricle 



Lymphatic 

 duct 



F VERTEBRATE 



B. COELENTERATE 

 Pseudocoel 

 Digestive tract 



Dorsal blood vessel 



Capillary 

 network 



Dorsal artery 



Capillary 

 network 



Coelom 



Vein 

 Lymph channel 



Fig. 196. Types of mechanisms for internal transport: A, "Sponge" type with "hated 

 channels. B, "Coelenterate" type. C. "Nematode" type with pseudocoel pnmary body 

 cavity. D, "Oligochaete" type with coelom and closed blood system. E, Crustacean- 

 molluscan" type with blood system opening to hemocoel which is derived from primary 

 body cavity or blastocoel. F, "Vertebrate" type with coelom, closed vascular system, and 

 lymphatic channels. 



sometimes called hemolymph, in these animals moves slowly back from the 

 tissue and the intercellular spaces and hemocoelic sinuses to the heart 



