158 Trails. Acad. Sci. of St. Louis. 



spots is more universal than in either of them, while the unspotted 

 abdomen relates it to N. f. erythrogaster of the same region. (Cope.) 



Habitat. — This species is restricted to Texas, Arkan- 

 sas, Oklahoma, and Missouri. Missouri localities : — P. R. 

 Tloy in his Journal of an Exploration of Western Mis- 

 souri in 1854 mentions the capture of Nerodia transversa 

 near Lexington, Lafayette Co., Mo., on May 12th. Last 

 year Mr. B. F. Bush of Courtney, Jackson Co., Mo., sent 

 me a specimen caught in that neighborhood. 



Habits. — Having never caught one of these snakes, I 

 can say nothing as to its habits, but, which, undoubtedly, 

 are very similar to those of other water snakes. 



50. Natrix grahamii Baird and Girard. Graham's 

 Water-Snake. 



Tropidonotus grahamii, Regina grahamii, Regina leheris var. grahami. 



Description. — ^Rostral broader than deep, visible from above. A single 

 nasal on each side obliquely grooved below the nostril. Two ante- 

 orbitals, two postorbitals, Internasals longer than broad, as long as 

 the prefrontals or a little shorter. Frontal one and two-thirds as long 

 as broad, as long as its distance from the end of the snout, shorter than 

 the parietals; loral as long as deep. Parietals large. Temporals 1-2. 

 Seven upper labials, third entering the eye; fourth and fifth the largest. 

 Lower labials ten; fourth and fifth the largest. Four lower labials in 

 contact with the anterior chin shields, which are much shorter than 

 the posterior. Head small, not distinct from the neck. Dorsal scale 

 rows nineteen, all keeled with the exception of the outermost, which 

 is very feebly keeled. The three outer rows sensibly the largest, with 

 the scales truncated posteriorly. Ventrals 156-173. Anal divided. 

 Subcaudals 54-65 pairs. Tail about two-tenths the length of the body. 



Color. — Olive brown above, uniform or with a lighter black edged 

 dorsal stripe. A broad yellowish or pale olive, black edged, stripe 

 along the three outer rows of scales. Upper lip and lower parts yel- 

 lowish, with or without a median black line or a series of spots on the 

 posterior part of the 'belly and under the tail. 



Habitat. — This species occurs from Michigan to Louis- 

 iana and Texas. Missouri localities: — St. Louis, Jeffer- 

 son, Jasper, Johnson, and St. Charles Counties. Illinois 

 localities: — Madison and St. Clair Counties. 



