330 W. BLAXLAND BENHAM. 



31. d'Udekem. — "Mem. s. les Lombriciens," 'Mem. d. I'Acad. Roy. de 



Beige,' XXXV, 1863. 



32. Vejdovsky. — 'System und Morph. d. Oligochaeten.' 



33. Vejdovsky. — " Das larvale uud definitiv Exkretionssystems," ' Zool. 



Anzeig.,' 1887, No. 260. 



EXPLANATION OF PLATES XXIII— XXV, 



Illustrating Dr. W. Blaxland Benliam^s paper ou ^' The 

 Nephridium of Lumbricus audits Blood-supply; with 

 Remarks on the Nephridia iu other Chsetopoda." 



^ (Where not otherwise stated, the drawings refer to Lumbricus 



herculeus, Sav.) 



Fig. 4. — The nephrostome or internal funnel, seen front in front and repre- 

 sented as slightly flattened, so as to show distinctly the various parts. Cilia 

 are omitted for the sake of clearness. The figure is fully named. The 

 central cell is left white. The vesicular connective-tissue cells (ves.) around 

 the prseseptal portion of the tube are represented only by their nuclei. 

 n. ccel. ep. is the flattened coelomic epithelium. The two fine concentric 

 lines near the centre of the funnel represent the boundaries of the actual 

 aperture, which places the tube in communication with the ccelom, and which is 

 further shown by the arrow. The line a is the inner limit of the large " central 

 cell," its outer limit being formed by the inner ends of the " marginal cells." 

 The line b is the thin outer free edge of the series of grooved centrifugal 

 cells, which are essentially drain-pipe cells, open along one side, or gutter- 

 cells. These two lines require not only a high power (Zeiss, 3, F), but a 

 particularly good clear preparation for their detection. 



Fig. 5. — A nephrostome drawn during life, to show the collection of leuco- 

 cytes or "debris" blocking the actual aperture of the funnel. These have 

 misled previous observers (see text). The cilia on the marginal cells are to 

 some extent diagrammatically represented, as only a few rows are drawn ; in 

 reality they cover the whole of the inner surface of the cells. The " gutter- 

 cells " are hidden by the superposed centripetal marginals. 



Fig. 6. — A funnel in profile, from a living specimen, showing leucocytes or 

 " debris." 



Fig. 6«. — A few of these leucocytes, showing pseudopodia. 



Fig. 7. — A longitudinal section through a funnel, from a series of sections 

 through a young worm [? sp.] (which were cut by my friend Mr. E. Goodrich). 

 The figure is fully explained. 



