In mammalian kidney the distal part of renal tubule returns to the vascular pole of its glomerulus, and is close to the glomerulus as macula densa, which is concerned with renin secretion. To investigate the situation in the holocephalian kidney, histological observations were made on the tissues of rabbitfish Chimaera monstrosa and ratfish Hydrolagus colliei. The results revealed that as in Elasmobranchii the distal segment of the renal tubule in Holocephali became contiguous to the vascular pole of the glomerulus, though no differentiation to macula densa was detectable. These findings in chondrochthyean kidney are marked contrast to those in osteichthyean kidney, where no such tendency is observable.