CONTRIBUTIONS TO THE ANATOMY OF THE HIRUDINEA. 505 



diurn lying in the perinephrostomial sinus, s. f. The funnel ; with n. n. nu- 

 clei, and V. vacuoles, a. The neck of the funnel, with ciliated lumen and 

 nucleus, r. The diverticulum, containing filaments and masses of blood-cor- 

 puscles. A very thin layer of cells may be seen covering the neck of the 

 funnel and parts of the diverticulum. Ccelomic epithelium, ep. In Fig. 53 

 several ccelomic epithelium cells, coel. ep., are seen floating in the sinus. 

 b. Blood sinus, communicating with the perinephrostomial sinus ; the other 

 communicating sinus is not visible, x. Point of communication of the nephri- 

 dial tubules with the funnel. 



Fig. 55. — Pontobdella. Filaments contained in the diverticulum of a 

 nephridial funnel, seen after staining with iodine. 



Fig. 56. — Pontobdella. Surface view of portion of the nephridial 

 tubules, to show the markings upon the surface. 



Fig. 57. — Pontobdella. Portion of the nephridial tubules, showing 

 nodules on tlie surface, n, n. Nuclei. 



Fig. 58. — Pontobdella. Portion of the nephridial tubules, showing blind 

 endings, n. Nucleus. 



Fig. 59 (Plate XXXII). — Pontobdella, (Nitric-acid, glycerine prepara- 

 tion.) neph. Network of nephridial tubules, with n. n. nuclei, cap. Net- 

 work of capillaries, gl. cl. Clitellar gland-cell and ducts, b, b. Connective- 

 tissue corpuscles. 



Fig. 60 (Plate XXXII).— Pontobdella. Network of nephridial tubules in 

 the fresh state, drawn to the same scale as Fig. 59, showing the extent to 

 which the lumen becomes distended. /. Lumen, n, n. Nuclei. 



Fig. 61 (Plate XXXIII). — Hirudo. Transverse section passing through 

 a pair of testes and nephridial funnels, but not a nephridium. al. The main 

 portion of the alimentary canal cut through in the centre, with sections of 

 csecal diverticula on either side. The pigment in the body wall is not shown, 

 a small portion being put in at x. See general references. 



Fig. 62 (Plate XXXIII. — Nephelis. Transverse section passing through 

 nephridial funnels and testes. See general references. 



Fig. 63 (Plate XXXIV). — Pontobdella. Halves of two transverse sec- 

 tions taken from different regions of the body. The left-hand half passes 

 through the first annulus of a somite, showing the papillae in section, one of 

 these containing the excretory canal of the nephridia, neph. apt., and another 

 the branchial dilatation, with portions of the sinus coming to it, hr. s. It also 

 passes through a nerve-ganglion, n. g. The right-hand half passes between 

 two annuli, and this shows little dermic region. It passes through a testis, t. 



Fig. 64 (Plate 5SXIV). — Clepsine. Transverse section passing through 

 two of the diverticula of the alimentary canal, and also through a pair of 

 nephridial funnels, neph. fun. 



These four figs., 61 — 64, are drawn to scale. For reference letters, see 

 above — general references. 



