174 REPTILES. 



ff. Snout not recurved and keeled ; species of large size. 

 g. Gastrosteges 130 to 155 ; general color 3 series of dark 

 blotches on a lighter ground, sometimes simply 

 barred or uniformly dark or reddish ; aquatic. 



Tropidonotus, 3. 



gg. Gastrosteges 200 to 235 ; general color brown or black, 

 sometimes with quadrate blotches; abdomen usually 

 blotched; terrestrial. . . . Coluber, 8. 



** Dorsal scales smooth. 

 X Anal plate entire; gastrosteges 175 to 200- color black, brown 

 or red, more or less variegated. 



h. Rows of scales 21 to 25 ; loral plate present. 



Ophibolus, 13. 



hh. Rows of scales 19 ; no loral plate. . . Osceola, 13. 

 XX Anal plate bifid; scales in 13 to 17 rows. 



». Gastrosteges 170 to 210; scales in 17 rows; snakes very 

 large or very long — ours lustrous pitch black in color 

 when adult. ..... Bascantum. 6. 



u. Gastrosteges less than 170; snakes of medium to small size. 



j. Scales in 13 rows ; gastrosteges 120 to 135 ; brown, salmon 

 color or yellowish beneath. . Carphophiops, 18. 



jj. Scales in 15 to 17 rows. 



Ic. Color black, unstriped ; a distinct yellowish ring about 

 neck ; gastrosteges 140 to 160. . Diadopiiis, 11. 



kk. Color clear bright green ; no collar ; gastrosteges 130 

 to 140 Cyclophis, 10. 



kkk. Color brownish, with black dots; no collar; gastro- 

 steges 115 to 125 Virginia, 17. 



XXX Anal plate bifid; scales in 19 rows; gastrosteges, 170 to 185. 

 I. Bluish black with squarish red spots on the blanks ; abdomen 



red with black spots Farancia, 14. 



U. Blue-black, with three red lines; abdomen yellowish with 

 a series of dark spots Abastor, 15. 



/. HETERODON, Beauvais. Spreading Adders. 

 1. H. plaiyrhinus, Latreille. Blowing Viper. Hog- 



