Branch Annulata 49 



short funnel-shaped tubes, the oviducts, which pass 

 through the partition to the fourteenth segment, and 

 thence through the body wall to the outside. These 

 furnish an exit for the contents of the ovaries. 



XIII. — Between the ninth and tenth, and between the tenth 

 'and eleventh segments, find two pairs of white pear- 

 shaped bodies ; these are the seminal receptacles. 



XIV. — Beginning with about the fourth segment, find in 

 the base of each segment except the last, and attached 

 to the posterior surface of the septum in front, long, 

 somewhat coiled, tubular organs. One end is free, but 

 terminates in the next anterior segment by passing directly 

 through the partition : the other end communicates with 

 the exterior. These are excretory organs called nephridia. 

 They are brought out distinctly by blowing alcohol upon 

 them through the tube of a wash bottle. 



the mariife annelid 



(nereis virens) 



This curious worm lives in the mud along the seashore 

 and the bottoms of tide marshes. It is of special interest 

 because it shows a more highly differentiated structure than 

 does the earthworm. 



I. — Study and describe the general shape of the body. 



What are the most important ways in which it differs 

 from the earthworm ? How many segments are there ? 



II. — How do' the appendages along the sides of the body 

 compare with the segments in number .■" Is it easier to 

 distinguish the anterior and posterior ends than in the 

 earthworm ? 



III. — Study the head : it has no appendages that project 

 laterally from the sides, and is divided into two general 



