Figure 9

Advanced stage of metanephridial system development in Lepidochitona corrugata (spm 10). A. Posterior part of specimen from dorsal with transparent external surface and planes (ortho slices) of section images shown in B–I. B. Total LM cross section through the anlagen of the metanephridial system with stippled rectangles indicating the position of details given in the TEM sections C and D. C. Opening of the renopericardial duct into the pericardium on left side. Stippled rectangle marks area shown in E. D. Left renopericardial duct. E. Cilia originating from wall of renopericardial duct. F. Total LM cross section through the anlagen of the metanephridial system with stippled rectangle indicating the position of details given in the TEM sections G–I. G. Ventral, left pericardial wall near the base of the atrium sitting atop the kidney. Stippled rectangles mark areas shown in H and I. H, I. Ultrafiltration sites, arrowheads indicate ultrafiltration slits. aj, adhaerens junction; bb, basal body; bm, basal membrane; ci, cilia; dgl, digestive gland; f, foot; h, heart, i, intestine; k, kidney; lln, left lateral nerve cord; mi, mitochondrium; mu, muscle fibers; mv, microvilli; nu, nucleus; pe, pericardium; r, rectum; rln, right lateral nerve cord; rp, renopericardial duct.