^°W'] PROCKEDINGS OF THE NATIONAL MUSEUM. 607 



OPHIBOLUS lid. and Oird. 



Cat. Kept. N. Amer. Pt. i, Serpents, 1853, p. 82. Cope, Check List North American 

 Batr. Reptilia, 'W, 1875 ; Proc. Amer. Philos. Soc, 1886, 487 ; Bull. U. S. Nat. Mus. 

 1687, p. 78. LampropeUis Fitzinger nomen nudum, Sj'Stema Reptiimiu, 1843, p. 25; 

 Cope, Proc. Acad. Phila., 18G0, p. 254. Splwnophis Fitz., loc. cit. nomen nudum, 

 liellophis Sockington, Proc. California Acad. Sci., 1877, p. .52. 



Posterior maxillaiy teeth larger and stronger than the anterior. 

 Head but little distinct. Cephalic scnta normal. Rostral plate not 

 modified; loreal present ; one preocnlar. Scales smooth, with two api- 

 cal pits. Anal scntnm entire; subcaudal scuta in two rows. Pupil 

 round. 



This genus represents in North America the Cororella of the Old 

 World, but is abundantly distinct in .its entire anal scutum and its 

 double scale pits. Its six species form a very homogeneous grouj), and 

 although they present abundant dilferences to the eye, critical examina- 

 tion shows that their characters are by no means easy to determine. 

 Some of them (0. doliatiis and 0. geUdns) otter a degree of variation 

 within themselves which is not equaled by any other North American 

 species, with the exception of the EuUvnia sirtalis. They aftbrd excel- 

 lent lessons in the evolution of specific types. 



The characters of the species are as follows : 



L Temporal scuta 2 (I) 2 (3) 3. 



Scales in twenty-one rows ; large brown or red dorsal spots or saddles broadly 



black bordered, forming pairs of black cross bands above O. doliatu8. 



II. Temporal scuta 2-3-4. 

 a Scales in 21 - 3 rows. 



Eight superior labials ; numerous brown dorsal saddle spots closed at the sides, 



O. muUi'itrdtus. 

 Seven superior labials; smaller, head wide, distinct, body slender ; numerous 



black rings more or less split with red O. pyrrliomelan. 



Seven labials; largo, robust, head little distinct; black with or without white 



transverse or longitudinal bands (). ijrtulua. 



Seven labials; robust, head not distinct; light brown, with snuiU transverse, 



reddish dorsal spots faintly dark bordered O. rhombomaculatuH. 



aa Scales in twenty-live rows. 



Seven labials ; robust; light brown with a median dorsal, and two lateral rows 

 of darker ])rown spots faintly dark bordered (). calUfjastcr. 



The distribution of these si)ecies is as follows : Tlie O. doliatus covl'Ih 

 North America east of the Rocky Mountains and south of latitude oO'^, 

 aud south to Panama. The 0. [letuliis has nearly the sanu? eastern 

 range, not reaching so far north by 10^, and covers the Sonoran and 

 Pacilic regions l)esides, but is scarcely' found in continental Mexico. 

 The 0. pyrrJiomelas inhabits the Sonoran and southern part of the 

 Pacific regions. Tiie 0. rlioinhomacnhitits occupies the middle regions 

 east of the Ap[)alachian Mountains, and the O. aillifjantcr the corre- 

 sponding region west of those mountains, and extends west as far as 

 the Pecos River of Texas. 



