VARIATIONS OF GARTER-SNAKES. 99 



By far the best account of the habits is that of Ditmars (1907, 

 220-221): 



In habits this snake appeals to the two preceding species [sauritus and sackcni]. It 

 is very quick in its motions, and appears to be perfectly at home in the water, swim- 

 ming with agility and extreme grace and diving to the bottom of a pond or stream 

 and there secreting itself among acpiatic plants. 



Captive specimens are very hardy, and will live indefniitely upon a diet of small 

 frogs or fishes. A number of specimens in the writer's collection were very fond of 

 climbing into a small branch that had been placed in their cage. Here they would 

 coil in a tight cluster, with heads protruding in every direction. Upon the intro- 

 duction of food they would dart for the prey in frenzied fashion, the lucky individ- 

 uals thrashing their tails violently as if to distract the attention of their hungry asso- 

 ciates from the morsels in the jaws of the former. One of these snakes gave birth to 

 fifteen young on the 24th of August. 



While our knowledge of its habits is thus very meager, from what 

 is known of the other forms in this grou}) I believe that, like them, 

 proximus will be found to be more aquatic in its habits than most of 

 the other forms of the genus. 



Range. — Proximus is known to occur on the coastal plain from the 

 eastern coast of British Honduras to the Mississippi River, and to 

 the northward of this j)lain and west of the Mississippi River in the 

 prairie-plains region and southeastern forest region of North America 

 to about the latitude of the northern boundary of Iowa. The eastern 

 coastal i)lain in Mexico is a low-lying tract of land bordering the 

 Gulf of Mexico. The climate is hot and humid, the temperatures 

 being tropical and the precipitation excessive. It is the "tierra 

 caliente" of the Mexicans, and is characterized by a rich tropical 

 flora that forms dense jungles. In Texas and Louisiana the coastal 

 plain conditions are similar to those in Mexico. Extensive tide- 

 w'ashed, brackish marshes occur all along the coast, and are accom- 

 panied on higher ground by a biota of distinct tropical affinities 

 (Bray, 1901, 102-103; Bailey, 1905, 16-18). 



The prairie regioji of North America has been briefly described. 

 The southeastern forest region, which occupies southeastern United 

 States south and east of the prairie region, is characterized by being 

 the principal area of development of the hard- wood forest; it is the 

 home of Quercus alba, Magnolia acuminata, Acer saccJiarum, Fagus 

 americana, Liriodendron tuUpifera, Fraxi7ius americana, Quercus 

 rubra, and Ilicoria alba. Transcau (1905) has shown that the region 

 is characterized by a rainfall evaporation ratio of 100-110 per cent 

 and that where this ratio falls to 80-100 per cent the flora merges 

 into that of the prairie region. The southeastern forest region to the 

 south of the prairie peninsula crosses the Mississippi and extends to 

 the eastern limit of the prairie, which, as j)reviously stated, is the 

 w^estern edge of the Ozark highlands and the 98th meridian. Proxi- 

 mus enters this region, then, only in its western part. 



