NEW ENGLISH GENUS OF AQUATIC OLIGOOH^TA. 179 



Fig. 19. It passes through the 18th somite behind the chsetse, close to the 

 spermidueal pore. The sperm-duct is quite superficial, tub. pub. Tubercula 

 pubertatis. 



YiG. 22. — Section through the male pore, from the same series as Figs. 19 

 and 21. sp. d. Sperm-duct, filled with spermatozoa, ep. Ordinary epidermis, 

 dipping in to meet the wall of the duct. b. v. Blood-vessels, cl. c. Clitellar 

 cells. 



Fig. 23. — A sperm-sac in longitudinal section, under a low power, sept. 

 Septum, ax. Axial group of muscle- (?) fibres, traversing the sperm-sae for 

 some distance, trab. Trabeculse of the same tissue ; various stages in the 

 development of the spermatozoa are indicated. 



Figs. 24 — 27 represent selected sections from a series through the oviducal 

 funnel, xiil, xiv, indicate the somites, sept. The intervening septum. Int. 

 Intestine. 



Fig. 24 passes through the opening of the funnel [ov.f.) into Somite xiii. 



Fig. 25. The next section of the series shows the folding of the funnel, 



and its bending over into the ovisac, ov.f. That part of the funnel 



communicating with Somite xiii, and which is cut along its edge. 



ov.f. That part opening into the ovisac. 



Fig. 26. Two sections further on : the opening of the ovisac into Somite 



XIII is past. The funnel {ov.f.) dips into the sac and lines one wall. 

 Fig. 27. The fifth section beyond the last ; still shows a small portion of 

 the funnel in the ovisac. 

 Fig. 28. — A section through the ovisac two sections further on than Fig. 

 27. A couple of ova are seen : each exhibits a karyokinetic figure. 



Fig. 29. — One of the ova represented in Fig. 28, much more magnified, 

 showing the nuclear spindle, chromosomes, and cytasters. It is probably 

 about to form directive corpuscles. The irregularity in the vitelline mem- 

 brane is due to reagents. 



Fig. 30. — A portion of a section through the clitellum. 

 Fig. 31. — A longitudinal section of a nephridial funnel, c. The nucleus of 

 the central cell. c. ep. Flat ccelomic epithelium covering the back of the 

 funnel, m. Marginal cells, ea:. m. Extra-marginal cells. 



Fig. 32. — A transverse section of a nephridial funnel, c. Central cell. 

 m. Marginal cells. em. m. Extra-marginal cells. c. ep. Flat ccelomic 

 epithelium. 



Fin, 33 represents a section through a spherical mass of cells lying in front 

 of a nephridial funnel {neph.f). y. Yellow granules embedded in the mass. 



