638 NORTH AMERICAN SNAKES COPE. 



deeply separating tlie elongate internasals. Pnpil rouud. Scales 

 smooth, bifossate. Anal and subcaudal scuta, entire. 



The i^roduction and recurvature of the rostral plate and entire anal 

 plate distiuguisli this genus from Coluber, which it resembles. It was 

 at one time thought to be allied to Pityophis in view of tlie presence of 

 the two characters in question, but the absence of the epiglottis and 

 undivided prefrontals show that it is distinct. There are several minor 

 characters, uot generic, which show that its affinities are not with the 

 species of Pityophis. Such are the peculiar form of the inferior labial, 

 prenasal, and loreal plates, and the very fine bristledike spicules of the 

 hemipenis, iu the American species at least. 



Two species are known which diflt'er as follows: 



Scales in from tweiity-seveu to thirty-oue rows; interiiasal plates decurved iu front ; 

 loreal elongate; temporals, 2-4; inferior labials i;5-14, the anterior narrow, sev- 

 ciitli largest. Tail less than one-sixth the length. Brownish gray with numer- 

 ous transverse brown dorsal spots, with alternating lateral spots li. elegans. 



Rhinechis elegans Kenu. 



Cope, Proc. Amer. Philos. Soc., 1885, p. 2S4; Arizona elegans Kennicott, U. S. Mex- 

 Bonud. Surv., ii, 1S59, Reptiles, p. 18; Pityojyhis elegans Cope, Check List Batr. 

 Rept. N. Amer., 1875, p. 3D. 



This species is subject to some variations. Thus in No. 426G there is 

 a small inferior preocular. In No. 1417G there are only twenty-seven 

 rows of scales, and there is a row of three temporals between the usual 

 2-4 scaled rows. 



This species is restricted in its range to the Sonoran region. The 

 most southern locality yet known is near the city of Chihuahua. The 

 most northern is north of the Cimarron Kiver, probably in Xew Mexico. 



M. Bocourt objects to my placing this species iu the genus Ehinechis, 

 as he says that the R. scalaris lias the anal plate divided. It is true 

 that Dumeril and Bibron state that tbis is the case, but on examining 

 four specimens from the Bonaparte Collection in the Museum of the 

 Philadelphia Academy of Natural Sciences I tind that the anal plate is 

 entire. 



PITYOPHIS Holbrook. 



North American Herpetology iv, 1842, p. 7, Bd. and Gird., Cat. Rept. N. Amer., Pt. i 

 Serpents, 1853, p. 04; Dumdril, Prodome des P>p. Gen., vii, 1^54, p. 2.02; Giiuther 

 Cat. Snakes, Brit. Mus., 1858; p. 85. -Cope, Bull.U. S. Nat. Mus., No. 32, 1887, p. 

 56; CliurchiUia Bd. and Gird., Reptiles in Stansbury's Expl. Gt. Salt Lake, 1852, 

 p. 350. 



Teeth of ecpial lengths. A vertical laminiform epiglottis. Cephabc 

 scuta normal except that each prefrontal is longitudinally divided into 

 two, producing four prefrontals. Kostral i)late more or less prominent, 

 and its superior angle produced backwards. Scales more or less keeled, 

 and with double apical i)its. Anal scutum entire; subcaudals in two 

 series. Pupil round. 



