AMERICAN NATURALIST 



Vol. XXXVII. January, igoj. No. 433 • 



THE WATER SNAKES OF SOUTHERN MICHIGAN. 



HUBERT LYMAN CLARK. 



The water snakes of the genus Natrix offer some puzzling 

 problems, not only to the systematist, but also to the student 

 of geographical distribution. There can be no doubt that much 

 of the difficulty is due to our lack of knowledge ; for, unfortu- 

 nately, the study of living snakes is not especially popular, 

 and preserved specimens are so apt to lose their normal colors 

 that the proper comparison of snakes from different localities 

 becomes a matter of very great difficulty. The occurrence of 

 a red-bellied water snake in southern Michigan has been known 

 for many years, but its relation to the common water snake, 

 Natrix fasciata sipedon (L.), has never been satisfactorily deter- 

 mined. It was with the hope of throwing some light upon the 

 solution of this problem that the work was undertaken, the 

 results of which are embodied in this paper. During the past 

 two years one hundred water snakes captured in the vicinity of 

 Olivet, Mich., have been examined, and careful observations 

 have been recorded, from the living or freshly killed specimens, 

 in regard to sex, size, proportions, and color, and the number of 

 scale rows, gastrosteges (plates on belly, in front of vent), and 



