Nitrogenous excretion in Chelonian reptiles

Abstract

Analyses for nitrogenous constituents were conducted on the urine of a series of Chelonian reptiles. Values obtained, as % of total N excreted for ammonia, urea, and uric acid, were Kinosternon subrubrum. 24, 23, 0.7; Pelusios der-bianus. 18, 24, 4.5; Emys orbicularis. 14, 47, 2.5; Kinixys erosa. 6, 61. 4; K. youngii. 6, 44, 5.5; Testudo denticulata 6, 29, 6.7; T. graeca 4, 22, 52; T. elegans 6, 8, 56. Amino acids accounted for 10-20%, allantoin 1-2%, guanine + xanthine less than 4% creatinine, trace, hippuric acid, none. The distribution of N excretion indicates that the aquatic forms excreted equal quantities of ammonia and urea, amphibian forms, urea, xerophilous terrestrial forms, uric acid. The results are correlated with Needham''s views that development of uricotelism is detd. by the condition of embryonic environment.