TECHNICAL NOTES AND BIBLIOGRAPHY 269 



That the reptiles are all characterized by the uric acid 

 habitus has a qualified exception in the turtles or Che- 

 Ionia, because in aquatic turtles uric acid rarely com- 

 prises more than 30 per cent of the total urinary nitro- 

 gen, and frequently the figure is less than 10 per cent. 

 Information on the Chelonia is limited and it is appro- 

 priate to refer here to some unpublished observations 

 made by the writer in 1925-1928 on fresh-water, ter- 

 restrial, and marine turtles. These observations conform 

 with the recorded data in showing that the urinary nitro- 

 gen in G. pseudographica, E. blandingii, K. subruhrum 

 hippocrepis, and Kinosternon sp,, C. marginata belli, P. 

 conccinna, P. elegans, and C. serpentina, is variably dis- 

 tributed between urea, uric acid, and ammonia, with 

 small quantities of creatine and creatinine. However, 

 these studies, like others reported in the literature, were 

 not carried out with proper consideration of the nutri- 

 tional condition of the animal, nor was consideration 

 given to the possible loss of lurea or ammonia through 

 anal sacs. 



In the marine turtles, Caretta kempi, C. caretta, Che- 

 lonia mydas, and Eretmochelys imbricata, examined at 

 the New York Aquarium through the courtesy of Dr. 

 C. M. Breder, only a small fraction (1.7 to 5 per cent) 

 of the urinary nitrogen in solution is uric acid, but the 

 urine frequently shows heavy mucilaginous strands that 

 are rich in this substance. Urea accounts for 26 to 85 

 per cent of the urinary nitrogen in a dozen samples, am- 

 monia for 1.5 to 25 per cent, vdth creatinine and creatine 

 representing less than 1 per cent each. The urea concen- 

 tration was highest in animals that were known to have 

 eaten recently. Thus the marine turtles do not appear 

 to differ from fresh-water forms in respect to the dis- 

 tribution of nitrogen in the bladder urine. 



A notable feature in these data, and one hitherto 

 overlooked, is that the urea content of the plasma and 

 perivisceral fluid in presimiptively healthy specimens of 

 Caretta kempi and C. caretta ranged from 340 to 400 



