THE REPTILES OF OHIO 9 



while field work was pursued in southwestern Ohio but no specimens were found. It 

 may occur in the Ohio River or in some of its tributaries. Hay (1892a, 573) records 

 it from southern Indiana. 



Use of Scientific Names 



The scientific names employed in the above hst and in the systematic list 

 of reptiles of Ohio are the same as those of Stejneger and Barbour (1933) 

 with the following exceptions: 



Leiolopisma unicolor (Harlan) replaces Leiolopisma laterale (Say) . See 

 Stejneger (1934, 182). 



Eumeces laticeps Schneider, not recognized by Stejneger and Barbour, is 

 here considered as distinct from Eumeces fasctatus (Linne) . 



Opheodrys vernalis (Harlan). The smooth green snake is referred to 

 the genus Opheodrys instead of to Liopeltis. See Schmidt and Necker (1936). 



Natrix erythrogaster erythrogaster (Forster), not recognized by Stejneger 

 and Barbour, is considered as specifically distinct from Natrix sipedon sipedon 

 (Linne) . 



Natrix sipedon insularum Conant and Clay has been described only re- 

 cently. (Conant and Clay, 1937) . 



Agkistrodon mokasen mokasen Beauvois is changed to subspecific status. 

 See Gloyd and Conant (1934). 



Crotalus horridus horridus Linne becomes a trinominal. See Gloyd (1935). 



Pseudemys scripta troostii (Holbrook). Viosca (1933) has shown that 

 Pseudemys elegans (Wied) is conspecific with Pseudemys troostii (Holbrook) 

 and Carr (1937) has further shown that Pseudemys scripta (Schoepff) inter- 

 grades with troostii in the Gulf coastal plain. 



Physiography and Geography of Ohio 



As numerous authors have shown, the distribution of animals frequently 

 is correlated with physiography. Thus a species may occur abundantly in one 

 region and be lacking in another, even though the two are adjacent geo- 

 graphically. In Ohio certain species of reptiles find their most suitable habi- 

 tats in limited portions of the state. In such cases it has been found that the 

 species in question is more or less confined to one or more of the physio- 

 graphic areas of Ohio. These areas are described in detail below and com- 

 ment is made upon the species inhabiting each of them. 



Portions of five physiographic areas are found within the limits of Ohio. 

 These are (1) the lake plains, (2) the till plains, (3) the glaciated Allegheny 

 plateau, (4) the unglaciated Allegheny plateau, and (5) the blue grass region 

 (see Map 1). Each of these areas is characterized by distinctive features which 

 are summarized below. 



1. The lake plains are bounded by old beach lines marking the maximum 

 limits of Lake Maumee in postglacial times. These plains cover a wide por- 

 tion of northwestern Ohio from Lake Erie to and beyond the Indiana boun- 



