112 



THE EARTHWORM 



one on each side and near the nerve cord. Immediately behind each 

 ovary is an oviduct, seen as a whitish area on the anterior face of the 

 septum between somites 13 and 14, and in somite 14 as a fine cord 

 which is very short and passes diagonally to its place of exit through 

 the ventral body wall. Locate these parts before pulling away the 



i-sae 



lumen _ 



, per/ - 



b/ood {/esse/s toneum 



Fig. 55.— Nephridium of earthworm. Above, diagram of an entire nephrid- 

 ium drawn with coils somewhat separated. Below (left), portion of 

 nephridium (7i) showing blood supply; (right) the nephridial funnel, or 

 nephrostome, by which the nephridium communicates with the ccelom; the 

 opening is between the dorsal and ventral lips. 



(Redrawn with modifications from G. B. Howes, "Atlas of Zootomy," copyright, 1902, by 

 Macmillan and Co., Ltd., printed by permission.) 



remains of septa and nephridia, which may partially obscure them. 

 Examine Fig. 56 and understand how the eggs pass from the ovary 



to the outside. 



(h) In sexually mature specimens, the seminal vesicles, which 

 should still be uninjured, consist of three lobes which extend dorsally 

 on each side of the esophagus and which are united by a common 

 median portion which lies against the ventral body wall. Careful 



