KIDNEY OF THE SUMATRAN RHINOCEROS, DICERORHINUS-SUMATRENSIS

The kidney of Diceros sumatrensis has the rhinocerotic form and lobati on. The ureter divides intrarenally into two fibromuscular conduits wh ich receive, at separate loci, the terminal collecting ducts of the lo bes. The kidney is 67% cortex. Total renal mass is 0.46% of body mass. There are about 34 lobes and 23 primary orifices at the conduits. Glo meruli are relatively small and of the same size across the cortex. Th ey number about 14.6 million in one kidney but the glomerular mass is relatively low. Unlike other rhinocerotic species, the kidney of D. su matrensis lacks interlobar septa. The interlobar arteries nevertheless enter the renal parenchyma as in the other rhinoceroses, i.e., betwee n the cortices of adjacent lobes rather than in the common mammalian m anner between cortex and medulla. Thus, internal ''perforator'' arteri es pass from cortical periphery to interior giving off cortical twigs on their way to the corticomedullary border, along which they branch w hile releasing centrifugal arteries back toward the cortical periphery . The arcuate veins are wide centrally where they enter the paracondui tal veins. The latter form prominent central anastomoses between the l arge interlobar veins. (C) 1993 Wiley-Liss, Inc.