metanephric mass of intermediate mesoderm, metanephric cap.
met·a·neph·ric mass of mes·o·derm
(met'a-nĕf'rik mas mez'ŏ-dĕrm) The mesoderm covering the distal end of the metanephric diverticulum; it gives rise to the nephrons in the permanent kidneys. Synonym(s): metanephric blastema.