ZooL.— Vol. IV] VAN DENBURGH—HYPSIGLENA AND ARIZONA 67 



round pupil. This is true of most alcoholic specimens, for 

 in these the pupil usually is dilated. In two living specimens, 

 however, I find that the pupil is slightly irregular in outline 

 so that it appears somewhat eccentric, that it varies consider- 

 ably in size from time to time, and that it is distinctly elliptic, 

 with the long diameter vertical, but becomes nearly round 

 when dilated. Some alcoholic specimens also show the 

 pupil somewhat contracted and elliptic. 



This point is of some importance, since the possession of 

 a vertically elongate pupil is in itself ample basis for the 

 recognition of the genus Arizona as distinct from the other 

 colubrine genera with which it has been confused. 



San Francisco, California, 

 February 24, 1906. 



