102 HARM NARAYAN HAHL 



Fig. 8. — Five consecutive longitudinal sections of a series taken from 

 the hinder portion of an embryo about 4 mm. long, showing the develop- 

 ment of piimary integumentary nophridia, and their relations with the 

 intersegmental septa, nph., nepluidia (integumentary) ; nph.c, nephridial 

 cells pushing their way into the septa ; i.s., intersegmental septum ; 

 c.c, coclomic cavity ; ect., ectoderm. 



Fig. 9. — A portion of a longitudinal section of the same embryo as in 

 lig. 8, showing the developing integumentary nephridia. Letters as in 

 Hg. 8. X 1,200. 



Fig. 10. — Portion of a longitudinal section of an embryo, showing the 

 semblance of a ' fuiuiel ', the only series in which a ' funnel ' is seen. 

 ,/'., pseudo-funnel, x 1,160. 



Fig. 11 (a-p). — A series of diagrams showing the developing stages of an 

 integumentary nephridium, taken from whole mounts of embryos with 

 endoderm and albumen removed. Nephridia lie posterior to the septa. 

 j.iS'., intersegmental septa ; s.l., short straight lobe of the nephridium ; 

 t.l., the twisted loop, x cir. 630. 



Fig. 12 (a-e). — A series of diagrams from whole mounts showing the 

 exact mode of development of a primary septal nephridium. /., the 

 prc-septal funnel ; s.l., straight lobe ; t.l., twisted loop ; t.d., terminal 

 dust; C.V., commissural vessel; i.s., intersegmental septum. xo30. 



Fig. 13. — Longitudinal sections of the posterior end of an embryo about 

 6 mm. in length, showing how the ' funnel-cell ' travels from its original 

 position in the nephridial layer of the body-wall to its final position on 

 the septa on each side of the dorsal vessel. 1-6 are sections of septa 

 from the same series showing the change in position, c.v., commissural 

 vessel ; f.c., funnel-cell ; v.lat.; ventro- lateral branches of the ventral 

 vessel ; c.c, coclomic cavities, x cir. 1,250. 



Fig. 14 (a-d). — A series of septa in longitudinal sections showing the 

 early development of a septal nephridium ventral and close to the com- 

 missural vessel and between the two sheets of mesoderm fomiing a septum. 

 b.iv., body-wall; c.v., commissural vessel; nph.r., nephridial rudiment. 

 X cir. 1,250. 



Fig. 15. — Two intersegmental septa with nephricUa on them from a whole 

 mount of an embryo about to hatch out of the cocoon, showing the develop- 

 ing secondary nephridia of both kinds, one with pre-septal funnel and the 

 other with post-septal funnel. ps)i., primary septal nephridium ; sec.s.n., 

 secondary septal nephridium with post-septal funnel ; sec.s.n'., secondary 

 septal nephridium with a pre-septal fumiel. x450. 



Fig. 16, — Part of a transverse section of an embryo, showing a rudiment 

 of a secondary septal nephridium. c.v., commissural vessel ; b.w., body- 

 wall ; n.c, nerve-cord ; d.v., dorsal vessel ; other letters as in fig. 15. 

 x330. 

 Fig. 17. — Portions of two consecutive sections of an embryo, showing 



