BATRACHIANS AND REPTILKS OF OHIO. 103 



39. Tail with a median crest of tubercles. — Chelydra serpentina — p. 139. 

 Tail without crest of tubercles. 40. 



40. Shell highest posteriorly. — Aromochelys odoratus — p. 139. 

 Shell highest at the middle. 41. 



41. Plastron hinged, capable of closing, more or less completely, the 



shell. 42. 

 Plastron without hinge. 43. 



42. Length of shell over 6 in. — Emynoidea blandingi — p. 141. 

 Length of shell less than 6 in. — Terrapene Carolina — p. 141. 



43. Shell with round yellow spots. — Clemmys guttatns — p. 140. 

 Shell without round yellow spots. 44. 



44. Shell keeled dorsally, notched behind. — 



Graplemys geographicus — p. 140. 

 Shell not keeled nor notched behind. 45. 



45. Plastron blotched with black. 46. 



Plastron not blotched with black. — Pseitdemys hieroglyphica — p. 140. 



46. Middle plates of carapace opposite each other. — 



Chrysemys picta — p. 140. 

 Middle plates of carapace alternating with each other. — 



Chrysemys marginata — p. 140. 



47. Dorsal part or tail bright blue. 48. 

 Dorsal part of tail not bright blue. 49. 



48. Black, with 5 yellow lines. — Eumeces quinquelineatus — p. 125. 

 Black, with 4 yellow lines. — Eumeces anthracinus — p. 125. 



49. A series of wavy lines running across body. — 



Sceloporus undulatns nndulatus — p. 123. 

 No wavy lines running across body. 50. 



50. Three yellow lines on each side of the body. — 



Cnemidophorus sexlineatus — p. 124. 

 A black and a white but no yellow bands on the sides. — 



Liolepisma laterale — p. 124. 



51. With rattles at the end of tail. 52. 

 Without rattles at end of tail. 53. 



52. Blotches on back numerous, smaller arranged in 7 series. Rattles stnalL 



Length never over 3 feet. — Sistrurus catenatus catenatus — p. 137. 



Blotches on back arranged in 3 rows, forming zig-zag cross-blotches.. 



Rattles large. Length 3^-5 feet. — Crotalus horridits—p. 138. 



53. With a pit between eye and nostril. — Ancisirodon contortrix — p. 137. 

 Without a pit between eye and nostril. 54. 



54. Body uniformly colored above, without markings. 55. 

 Body with markings above. 62. 



55. Color brown. 56. 



Color greenish or black. 57. 



56. Scales smooth. — Carphophiops amoenus — p. 125. 

 Scales rough. — Natrix fasciata ei ythrogaster — p. 131. 



57. End of snout upturned. Body short and thick. — 



Heterodon platyrhinus — p. 126. 

 End of snout not upturned. 58. 



58. Scales rough. 59. 



Scales smooth. — Liopeltis vernalis — p. 127. 



59. Greenish below. 60. 



Yellowish below. — Clonophis aestivus — p. 12S. 



