VARIATIONS OF GARTER-SNAKES. 91 



between August 7 and 20, a difference of thirteen days. This is an 

 unusual occurrence among the garter-snakes, and is undoubtedly 

 abnormal, for, as far as we have observed, it has been invariably 

 the rule that the entire brood appeared within a few hours at most. 

 We have seen but one other specimen give birth to young, and there 

 were four in this brood. The young when but a few days old will 

 struggle eagerly with earthworms or minnows, capturing the latter 

 in a small dish of water or taking them from the fingers. For the 

 first three or four da3^s they are very secretive and can be seen only 

 by overturning the moss and stones in the cage, except when they 

 come out to feed. They have not been observed to feed during the 

 first three days, but after tliis they will come out freely to gorge 

 themselves on fish, returning again beneath the stones when satis- 

 fied. One of these young snakes was kept for three months, in wliich 

 time it attained to the respectable length of 150 mm. 



Range. - The area occupied b}^ hutleri may be considered geograph- 

 ically as an extension of the prairie-plains region, which gradually rises 

 to the eastward and merges with the Allegheny plateau. The entire 

 region was overridden by the ice sheets of the Glacial epoch, and the 

 topography is determined by the thick mantle of glacial waste which 

 has been spread over the underlying rock surface, as till sheets, 

 moraines, outwash aprons, etc. The drainage is entirely to the 

 Mississippi by way of the Ohio and its tributaries, with the excep- 

 tion of the small area in southern Michigan, northern Ohio, and 

 northwestern Pennsylvania, which lies witliin the drainage basin of 

 the Great Lakes. 



The climate of the region is for the most part mild and rather 

 humid, as is evinced by the character of the vegetation. The whole 

 region is forested, with the exception of small scattered patches of 

 prairie and a small area in western Indiana and southwestern Michi- 

 gan, wliich is encroached upon by the extreme eastern end of the 

 prairie peninsula. The rainfall of 30-35 inches that characterizes 

 the prairie increases in this region to about 40 inches, and with this 

 increase, as Transeau (1905) has shown, there is also a rise in the 

 rainfall-evaporation ratios to 80-100 per cent. The forest is of the 

 broad-leafed deciduous type of southeastern North America, but as 

 over the greater part of the region under consideration (Ohio, Indiana, 

 southern Michigan) the rainfall is less and the evaporation greater 

 than in the southern Appalachians, wnere tliis forest has its principal 

 development, the condition may be considered intermediate between 

 those that accompany the development of the forest in the south- 

 eastern United States and those wliich obtain on the prairie, and the 

 effect of the diflerence of conditions upon the vegetation is shown by 

 the more open character of the woods on the uplands. It is generally 



