194 EEPTILIA: OPHIDIA. xxvm. 



278. NATRIX Laurenti. (Tropidonotus Kuhl.) 



a. Scales in 23 to 25 rows. 

 b. Rostral plate single. 



551 . N. sipedoii (L.). WATER SNAKE. " MOCCASIN." Brown- 

 ish, back and sides each with a series of large, square, dark blotches 

 alternating with each other ; about 80 in each series ; rarely uni- 

 form brownish; belly with brown blotches. Scales, 23. V. P. 130 

 to 150. L. 30 to 50. N. Eng. to Kan. and S. ; very abundant 

 about streams, feeding on fishes and frogs. Variable ; an unpleasant 

 and ill-tempered, but perfectly harmless snake. Prominent varie- 

 ties are var. woodhousei Baird & Girard : color of Sipedon, a narrow 

 whitish line between dorsal blotches. Scales 25. S. 111. to Texas. 

 Var. erythrogaster Shaw, uniform red-black above, coppery below ; 

 head long ; scales strongly keeled ; Mich, to Kan. and S. 



552. N. fasciatus (L.). SOUTHERN WATER SNAKE. Dark 

 brown, with transverse black blotches on back and about 35 oblong 

 red spots on sides; back sometimes with broken rings of yellow 

 dots; belly reddish, usually blotched. Scales 25. V. P. 128 to 

 135. S. Ind. (Ridgway} to Texas and S. E., swarming in the 

 lowland swamps S., doubtless varying into N. sipedon. 



bb. Rostral plate divided into two by a vertical suture. 



553. N. bisectus (Cope). Olive brown, a row of small blackish 

 spots on side ; head and belly nearly plain. V. P. 143. Scales 

 25. One specimen from Washington, D. C. 



aa. Scales in 27 to 33 rows. 



554. N. cyclopion (Durneril & Bibron). Plumbeous, with al- 

 ternating blackish vertical bars 1 to ITT scales wide. V. P. 140 to 

 150. Scales 27 to 33. S. 111. to Fla. ~ (tcvKXa)^, round-eyed.) 



555. N. rhombifer (Hallowell). Brown with about 50 black quad- 

 rangular blotches bordered by black lines. Scales 27, all keeled. 

 V. P. 140 to 145. Mich, to 111. and S. W. (Lat., bearing rhombs.) 



279. CALLOPELTIS Bonaparte. (xaXos, beautiful ; 



TreAri?, shield.) 



a. Body without longitudinal brown stripes. 

 b. Scales in 25 to 27 rows. 



c. Vertical plate longer than broad. 



556. C. guttatus (L.). CORN SNAKE. Red brown with a dorsal 

 series of large, red, dark-edged blotches ; belly checkered with 

 black. Scales 27. V. P. 210 to 230. L. 50. Va. and S. (Lat., 

 spotted.) 



557. C. obsoletus (Say). PILOT SNAKE. Lustrous black, some 

 scales white-edged ; belly slaty-black ; median scales of back ob- 

 scurely keeled, the rest smooth. Scales 27. V. P. 235. L. 50 to 

 75. Mass, to 111. and Texas; one of our largest snakes, often 

 climbing trees to a great height by following the depressions in 



