COLUBRID^B. LXXV. 175 



/ 



NOSE SNAKE. Brownish, with about 28 dark dorsal 

 blotches, besides lateral ones and half rings on the tail; 

 sometimes uniform black. Vertical plate longer than 

 broad, about equal to occipitals; L. 30; G. 125 to 150; 

 scales 25. E. U. S., abundant. A very variable species; 

 when angry it depresses and expands the head, hissing 

 furiously, thus exhibiting a very threatening appearance, 

 but it is perfectly harmless. 



2. H. simus, (L.) Holbrook. HOG- NOSED SNAKE. 

 Dorsal blotches about 35; ground color usually paler or 

 yellowish brown ; vertical plate much longer than occip- 

 itals, broader than long; G. 130; scales 23 to 27, usually 

 25. Southern, N. to Ills, and Wis. 



2. TROPIDONOTUS, Kuhl. WATER SNAKES. 

 * Scales in 23 to 29 rows. (Nerodia, B. & G.) 



1. T. sipedon, (L.) Holbr. WATER SNAKE. WATER 

 ADDER. Brownish ; back and sides with each a series of 

 large, square, dark blotches alternating with each other; 

 rarely uniformly dusky; scales 23; G. 130 to 150; L. 30 

 to 50. E. U. S., abundant; aquatic. 



Var. erythrog aster, (Shaw) Cope. RED -BELLIED 

 WATER SNAKE. Uniform red-black above; copper-color 

 below; head elongated. Michigan to Kansas and S. 



Var. woodhousei, (B. & G.) Cope. Scales in 25 rows. 

 Mo. to Texas. 



2. T. rhombifer, Hallowell. HOLBROOK'S WATER 

 SNAKE. Brown, with black quadrangular blotches; 

 scales in 27 rows. Mich., Ills, and S. 



** Scales in 19 to 21 rows. (Regina, B. & G.) 



3. T. rigidus, (Say) Holbr. STIFF SNAKE. Greenish 

 brown; two brown dorsal bands; abdomen yellowish, 

 spotted; outer row of scales smooth; scales 19; G. 130 

 to 170; L. 24. Penn. to Ga. 



