138 BULLETIN Gl, UNITED STATES NATIONAL MUSEUM. 



ELEGANS.a 



Description. — On the high plateau region and in the Sierra Nevada- 

 Cascade and Rocky Mountain ranges of North America occurs one 

 of the best knouai and least well-defined forms in the genus. This 

 form, as here understood, consists of the snakes usually referred to 

 vagrans and in part also to elegans, hiscutata, infernalis, and lineo- 

 lataJ' The lateral stripes are on the second and third scale rows, 

 the dorsal usually on the median and a varying amount of the adja- 

 cent rows, being usually encroached u})on by the spots of the upper 

 series. Both dorsal and lateral stripes often indistinct, the dorsal 

 occasionally absent for a part or all of the length. Dorsal scale 

 rows, 21-19-17 or 19-21-19-17; labials, 7/9, 7/10, 8/9, 8/10, or 8/11; 

 preoculars, 1 or 2; postoculars, 2, 3, or 4; subcaudals, 65-79 

 (females), 80-96 (inales) ; ventrals, 152-109 (females), 163-182 

 (males). 



The form is moderately robust, tail length about .18-.24 in females, 

 .24-. 276 in males, although these limits are rarely attained. Head 

 distinct, eye small. Postgenials usually as short or shorter than the 

 preceding pair, but occasionally longer. Two rows of alternating 

 black spots on either side between the lateral and dorsal stripes, 

 which are usually, although not always, distinct on the scales (see 

 frontispiece). Nuchal blotches usually rather small, and generally 

 interrupted by the lighter keels of the scales. Head brownish, often 

 considerably marked with black. Labials only narrowly margined, 

 if at all. 



Habits and liaMtat relations.— The form apparently differs little 

 from the other garter-snakes in preferring the proximity of water, 

 either in the form of marshes, ponds, lakes, or streams. Various 

 writers describe its habits as follows: Coues (1875, 614-615): "My 

 specimens were found along the Zuni River in New Mexico wherever 

 this stream spreads into sluggish lagoons, basking on the floating 

 plants or swimming freely in the water like a Nerodia or Regina.'' 

 Merriam (1891, 15): "Several garter-snakes {Eutsenia vagrans) 

 were found in the water in small, cold streams emptying into Salmon 

 River a few miles north of Round Valley." Cope (of his variety 



a Thamnophis ordinoides elegans (Baird and Girard), Catalogue of North American 

 Reptiles, 1853, pp. 34-36. Includes Eutxnia vagrans Baird and Girard, E. bis- 

 cutata Cope, T. vagrans biscutataYAn Denburoh (part.), E. infernalis Cope, E. elegans 

 lineolata Cope, E. elegans brunnea Cope, E. henshavn Yarrow, E. couchi Kennicott, 

 and E. vagrans plutonia Yarrow. 



b My conception of this and the following form will appear strange to most herpetol- 

 ogists. A careful study of the material, however has shown that it is impossible to 

 recognize the forms vagrans, elegans, lineolata, atrata, leptocephala, trilineata, and bis- 

 cutala as they are usually defined. In fact a perusal of the literature will show that no 

 two writers are agreed as to the importance of the several forms that have 

 been described. 



