THE ORIGIN OF THE ELECTRIC ORGANS IN ASTRO- 

 SCOPUS GUTTATUS. 



By E. Grace White. 



INTRODUCTION. 



Living organisms, aside from expending energy in the growth, differ- 

 entiation, and reproduction of their bodies and in secreting many sub- 

 stances useful in the preservation of their lives, may also release energy 

 in the form of motion, electricity, heat, and light, all of which may 

 play a more or less important part in the maintenance of Ufe. Of these 

 powers, that of producing electricity specifically and in quantities large 

 enough to be of use to the organism is confined to seven groups of 

 fishes, two of which are elasmobranchs and five teleosts. The same 

 power has been reported to be present in a snail and in some insects, 

 but these reports have not been confirmed. It seems clear that among 

 the fishes the power to produce electricity has been developed inde- 

 pendently in the seven groups mentioned. All the activities of cells, 

 such as secretion, motion, or nerve-conduction are accompanied by the 

 release of a very small amount of electric energy, which apparently can 

 not be of any possible use to the animal. Are the powerful electric 

 discharges, sometimes over 100 volts in strength, which occur in these 

 seven groups of fishes the result of evolutionary processes that first 

 took their origin in the very minute electric discharge of the ordinary 

 forms of tissue-cells? 



A begmning to an answer to this question may be made by studying 

 the structure of the electric organs, and particularly their morphologi- 

 cal and cytological development in the ontogeny of the forms. This 

 the writer has attempted to do, as suggested by Professor Ulric Dahl- 

 gren, of Princeton University, in the case of the remarkable electric 

 organ of Astroscojjus guttatus and Astroscopus y-grcecum. I wish 

 here to express my gratitude to Professor Dahlgren for his generous 

 offer of the material, for his kindly direction of the problem, and for 

 his most valuable criticisms. I wish also to thank Professor E. G. 

 Conklin, of Princeton Universitj^, and Professor E. B. Wilson, of 

 Columbia University, for reading and criticizing the paper. The 

 expenses of collecting the material for this work were met by donations 

 extending over a series of years from the Carnegie Institution of Wash- 

 ington, through the kindness and interest of Dr. A. G. Mayer. 



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