RENAL VASCULATURE OF 2 DASYURID MARSUPIALS, SMINTHOPSIS-DOLICHURA ANDS-CRASSICAUDATA

The renal vasculature of two dasyurid marsupials, Sminthopsis dolichur a and S. crassicaudata, was examined using scanning electron microscop y of vascular corrosion casts of the kidney. Each species had a pair o f unipapillary kidneys and the structural organisation of the major re nal arterial vessels was similar to that of other placental mammals. T he glomerulus of both species consisted of a network of dividing and a nastomosing capillary loops. The glomeruli varied markedly in size, sh ape and complexity. Some afferent arterioles extended back towards the renal medulla, positioning the glomeruli closer to the cortico-medull ary border. This placement of glomeruli may extend the loop of the nep hron further into the medulla and thereby enhance counter-current wate r reabsorption and the final urine concentration. In both S. crassicau data and S. dolichura, a dense mesh of numerous fine capillaries lined the wall of the renal pelvis adjacent to the inner medulla, with a un ique configuration in that they were aligned perpendicular to the vasa recta. The function of these fine capillaries is unknown.