142 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



prominences, which are used as organs of adhesion during 

 the act of copulation. The two pairs of inner setae of 

 each of these segments are situated near the outer ends of 

 these prominences, and are larger than those of the adja- 

 cent segments. 



d. On the sides of the body, in a line with the outer 

 setae, and between the ninth and tenth, and tenth and 

 eleventh segments, are the external apertures of the four 

 seminal receptacles. 



e. On the fourteenth segment, just exterior to the setae 

 of the inner row, are the openings of the oviducts. These 

 are very small, but, in a large specimen, they may be seen 

 with a lens after the cuticle has been removed. 



f. On the fifteenth segment, just outside the inner 

 setae, are two somewhat prominent papillae, each of which 

 has a slit-like aperture, the orifice of the vas deferens, or 

 male reproductive aperture. 



g. Segments twenty-nine to thirty-six have already 

 been noticed as the girdle. Posterior to the thirty-sixth, 

 the segments suddenly decrease in width, and are then 

 repeated, with little modification, to the posterior end. 



h. On the median dorsal line there is a roAV of pores, 

 one on the anterior margin of each segment, by which the 

 body-cavity opens externally. 



n. General Anatomy. 



A large specimen should be selected for dissection, and 

 killed by placing it for a few minutes in a bottle or tum- 

 bler with a few drops of ether. With a sharp knife or a 

 pair of fine-pointed scissors make an incision along the 

 median dorsal line, and pin out the integument of the 

 anterior third of the body, under water. 



1 . The perivisceral Jluid. 



The body cavity will be found to contain, especially in 



