194 REPTILIA: OPHIDIA. — XXVIII. 



278. TROPIDONOTUS Kubl. (rpoW, keel ; varos, back.) 



a. Scales in 23 to 25 rows. 

 b. Rostral plate single. 



551. T. sipedon (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. T. 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. 



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



553. T. 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. T. cyclopium Dumeril & Bibron. Plumbeous, with al- 

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

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



555. T. 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. COLUBER Linnaeus. (Old name of some snake.) 



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 



