n6 



ANIMAL BIOLOGY 



The body of the worm is divided by a number of septa, 

 or partitions, extending from the digestive tube to the 

 body wall, each septum' forming the boundary between 

 two segments of the body. The digestive tube extends 

 straight from the mouth to the anus in the last segment, 

 and is divided into a number of parts. Behind the mouth 



Ph 



FIG. 99. Internal organs of earthworm, br, brain; c, crop; g, gizzard; 

 h, hearts arising from the dorsal blood vessel; n, nephridia; oe, esophagus; 

 ph, pharynx; sr, seminal receptacle; sv, seminal vesicles. (After Hatschek 

 and Cori.) 



is a muscular pharynx which is used in drawing things in. 

 This is followed by a short esophagus, leading to a thin- 

 walled enlargement, called the crop, closely behind which 

 is a thick- walled muscular organ, the gizzard, which serves 

 as a grinding apparatus. Behind the gizzard is the in- 



