Johnson — Axial Bifurcation in Snakes. 529 



milk snake ten inches long. Judging from the photograph 

 reproduced in the paper, the degree of bifurcation was most 

 nearly like that in Case XII. 



Dr. J. S. Kingsley in describing an abnormal frog in the 

 American JSTaturalist, Vol. XII, pp. 694-695, states that a 

 two-headed snake is in the collection of the Lyceum of IN'atu- 

 ral History at Williams College. Prof. S. F. Clark informs 

 me, however, that the snake probably referred to is one which 

 merely simulates this condition from having been crushed. 



Mr. Samuel Garman tells me that this abnormality may be 

 found frequently in embryoes of Tropidonotus fasciata sipedon 

 Linn. 



RESUME OF ALL CASES DESCRIBED. 



Table III records the more important data gathered from 

 previous descriptions of two-headed snakes v/hich are suffi- 

 ciently complete. 



