194 REPTILIA : OPHIDIA. — XXVIII. 
278. NATRIX Laurenti. (Tropidonotus Kuhl.) 
a. Scales in 23 to 25 rows. 
6. Rostral plate single. 
551. N. 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, Ill. 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.). SourHern Water Snaxe. 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. 8S. Ind. (Ridgway) to Texas and S. E., swarming in the 
lowland swamps S., doubtless varying into NM, sipedon. 
bb. Rostra! plate divided into two by a vertical suture. 
553. IN. 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 (Duméril & Bibron). Plumbeous, with al- 
ternating blackish vertical bars 1 to 1} scales wide. V. P. 140 to 
150. Scales 27 to 33. S. Tl. to Fla. (ki«Awy, 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 Ill. and S. W. (Lat., bearing rhombs.) 
279. CALLOPELTIS Bonaparte. (xados, beautiful ; 
mé\rn, shield.) 
a. Body without longitudinal brown stripes. 
b. Scales in 25 to 27 rows. 
ce. 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. Wa.andS. (Lat., 
spotted.) 
557. C. obsoletus (Say). Pitot Snaxe. Lustrous black, some 
scales white-edged; belly slaty-black; median scales of back ob- 
securely keeled, the rest smooth. Scales 27. V. P. 235. L. 50 to 
75. Mass. to Ill. and Texas; one of our largest snakes, often 
climbing trees to a great height by following the depressions in 
