A NEW GENUS OF OLIGOCH^TA. 487 



(16) Bergh, R. S. — "Zur Bilduugsgeschiclite der Exkretionsorgane bei 



Criodrilus," ' Arbeiten Zool.-Zoot. lust. Wiirzburg,' Bd. viii, p. 223. 



(17) Lang, S.— " Die Polycladen," in ' Naples Monographs.' 



(18) Spencer, W. B.— " The Anatomy of Megascolides australis," 



'Trans. Roy. Soc. Victoria,' vol. i, pt. i. 



(19) Wheeler, W. W.— •' The Embryology of Blattagermanicaand 



Doryphora decemlineata," 'J. Morph.,' vol. iii, p. 291. 



DESCRIPTION OF PLATES XXXIII and XXXIIIa, 



Illustrating Mr. Frank E. Beddard's paper " On the Structure 

 of a New Genus of Oligochseta (Deodrilus), and on the 

 Presence of Anal Nephridia in Acanthodrilus." 



Figs. 1 — 11. — Acanthodrilus multiporus and nephridia. 



Fig. 1. Dorsal half of the posterior twenty or thirty segments of Acan- 

 thodrilus multiporus, enlarged to twice the natural size. 



Fig. 2. Part of a network of nephridia. The fusion of the tubules is so 

 complete as to produce the impression of a system of lacunar spaces. 



Fig. 3. Connective tissue from outer coat of rectum, n. Nuclei, v. 

 Spaces. 



Fig. 4. A portion of connective-tissue sheath of rectum, with contained 

 nephridial tubes, m. Muscular fibres, v. Spaces, bl. Blood-vessels. 

 n. Small tubule apparently contained in a larger one. 



Fig. 5. Part of a transverse section through rectum, ep. Lining epi- 

 thelium. 71. Nephridial tubules in connective-tissue sheath. 



Fig. 6. Part of Fig. 5, more highly magnified to illustrate structure of 



different regions of anal nephridia, N., N'n. 

 Fig. 7. Network of tubules l^iug in and upon septum, a. Muscular 



fibre, n. Walls of nephridium. 

 Fig. 8. Mass of tubules passing up septa, the relations of which are 



shown in Fig. 9. bl. Blood-vessels. a,b,c,d. Nephridial tubes, 



Fig. 9. Longitudinal section through a portion of rectal wall. o. Orifice 

 of anal nephridium. sp. Intersegmental septum. 



Fig. 10. Section through point quite close to opening of nephridium into 

 rectum. N. Nephridium. E. Epithelium of rectum continuous with 

 nephridium. 



