EAETHWOEM 127 



one on each side, external to the ventral setse 

 in the fifteenth segment. "What is the shape 

 of the opening ? Direction ? 

 (h) The opening of the oviduct or duct of the ovary ^ 

 situated similarly to {a), but in the fourteenth 

 segment. Compare with (a) in all respects, 

 (c) Hie openings of the spermathecce or seminal re- 

 ceptacles, two pairs of openings situated in a 

 line with the outer row of bristles and in the 

 grooves between segments nine and ten, and 

 ten and eleven, one pair in each groove. Com- 

 pare with {a) and (5). 

 Make an outline drawing of the body as' before, but 

 of the ventral side, indicate the number of segments 

 back to the girdle, and the openings of the sexual or- 

 gans. 



((f) The capsulogenous glands. — The swollen ven- 

 tral surface of segments nine to eleven or 

 sometimes eight to twelve is due to the pres- 

 ence of these glands. 



Internal Anatomy. — Put the largest available pre- 

 served specimen into a dissecting-pan with enough fifty 

 per cent, alcohol to cover the worm. Pin the body 

 out straight, dorsal side uppermost, thrusting the pins 

 through the first and one of the last segments. "With 

 a pair of sharp, fine-pointed scissors cut through the 

 body-wall along the median dorsal line from about 

 the seventieth to the first segment. Carefully cut the 

 membranous partitions or septa at the points where 

 they join the body-wall, and pin back the flaps of the 

 latter. Notice that the body-wall forms a tube in 

 whose cavity, the body-cavity or peri- visceral cav- 

 ity, lies another tube, the alimentary canal ; also that 



