384. ALFRED GIBBS BOURNE. 
backward. The excretory ducts of the nephridia of Segments x and x1, 
neph. 10, neph. 11, are shown. pr. Prostate. v. d. Sperm duct. 0. s., i. 8. 
Outer and inner seta lines. 
Fic. 50. Diagrammatic drawing from a thick longitudinal section to show 
the relations of the oviducal wall, ovd. Other letters as before. 
Fic. 51.—The ovisacs, ovs., and the portion of Segment x1 which contains 
the ovaries filled with ova, drawn the natural size. 
Fic. 52.—“ Ciliated rosette,’ as seen on opening the sperm-sac. The 
portion of the sperm-duct drawn is seen through the wall of the sac. 
Fic. 53.—Sperm-duct in transverse section. A loop bound together by 
the connective tissue of the ‘‘ mesentery,” the duct cut across twice. 
Fic. 54.—Portion of the sperm-duct in longitudinal optical section. c. ¢. 
Connective tissue. ep. Epithelium. 
Fic. 55.—Longitudinal section passing through the papilla protruded at 
the male pore. aé¢. Atrium. pv. Prostate. musc. Muscle covering the pros- 
tate. v. ad. Sperm-duct about to open into the atrium. 
Fie. 56.—Small portion of the same section more highly magnified, show- 
ing the gland cells of the prostate and their ducts. 
Fic. 57.—From a section across the ovary, ov., including a portion of the 
oviducal wall. This shows the epithelium of the oviduct becoming continuous 
at a. with the ccelomic epithelium. 
Fics. 58 and 59.—Longitudinal sections from a young individual 140 mm. 
long. 7. Testis. f Ciliated rosette. Other letters as before. The copulatory 
pouch is not yet developed. 
