TECHNICAL NOTES AND BIBLIOGRAPHY 25 1 



That the reduction in blood-urea content of fresh- 

 water elasmobranchs is not a reversal of evolution is 

 stated as a rebuttal to Needham {67}. 



VI. THE LUNGFISH 



74. Atz, J. W. Narial breathing in fishes and the evo- 

 lution of internal nares. Quarterly Review of Biology, 

 27: 366. 1953. 



75. Baldvtin, E. An Introduction to Comparative Bio- 

 chemistry. Macmillan Company, New York, 1937. 



76. Florkin, M. Biochemical Evolution. Translated by 

 S. Morguhs, Academic Press, Inc., New York, 1949. 



77 . RoMER, A. S. The braincase of the carboniferous 

 crossopterygian Megalichthys nitidus. Bulletin of the 

 Museum of Comparative Zoology (Harvard), 82: 



3- 1937- 



78. RoMER, A. S. and E. C. Olson. Aestivation in a 

 Permian lungfish, Breviora. Museum of Comparative 

 Zoology, 30: 1. 1954. 



79. Smith, H. W. The excretion of ammonia and urea 

 by the gills of fish. Journal of Biological Chemistry, 

 81: 72,7. 1929. 



80. Smith, H. W. Metabolism of the lung-fish, Pro- 

 topterus aethiopicus. Journal of Biological Chemis- 

 try, 88: 97. 1930. 



81. Smith, H. W. Observations on the African lung- 

 fish, Protopterus aethiopicus, and on evolution from 

 water to land environments. Ecology, 12: 164. 1931. 



82. Smith, H. W. Kamongo. Viking Press, Inc., New 

 York, 1932. Revised edition, 1949. Kamongo, or the 

 Lungfish and the Padre. Compass Books, Viking 

 Press, Inc., New York, 1956. 



83. Smith, H. W. The metabolism of the lung-fish. I. 

 General considerations of the fasting metabolism in 

 active fish. Journal of Cellular and Comparative 

 Physiology, 6: 43. 1935. 



84. Smith, H. W. The metabolism of the lung-fish. II. 



