SYNOPSES AND DESCRIPTIONS. 73 
with a narrow black line. Dorsal scales in 15 rows. Ventrals 193. Anal 
entire. Subcaudals 57 pairs. (From descr.) Rio San Pedro of Rio 
Grande. 
DIADOPHIS REGALIS. 
Baird & Girard, 1853, Cat. N. A. Serp., 115. 
‘Body above uniform greenish-ash; beneath light yellow, scattered all 
over with small black spots. No occipital ring. Dorsal scales ‘in 17 
rows. Ventrals 237+14:58 pairs.” Sonora, Mexico. 
A specimen of this species from San Luis Potosi has 210 ventrals. 
Anal bifid, and 73 pairs of subcaudals. The lower surface of the tail and 
hinder abdomen are a bright orange red, shading to yellow forward. Belly 
spotted irregularly with black. Labials and chin-shields with black spots 
on their hinder margins. Scales in the outer row dark with yellow bases, 
medials dark, finely sprinkled with ashy. 
The three preceding species of Diadophis are very closely related. I 
am inclined to consider them as one, which, through several varieties, 
gradually increases in length, number of ventral plates and brilliancy of 
coloration from New England to Mexico. 
RHINOCHEILUS. 
Baird & Girard, 1853. 
Body elongate, tapering little to head and tail, slightly compressed; head 
small, rather indistinct, narrow, crown convex, snout produced, pointed; 
tail short, tapering regularly. Maxillary teeth equal, smooth, without 
interspaces between anterior and posterior. Crown-shields nine. Rostral 
prominent, bent back on the top of the snout. Nasal in two parts, nostril 
between. Loreal present. Oculars 1—2. Scales smooth, short, broad, 
in 23 rows. Anal entire. Subcaudals entire or divided (the specimen 
before me has nineteen of the posterior divided). 
RHINOCHEILUS LECONTEI. 
Baird & Girard, 1853, Cat. N. A. Serp., 120. 
Long, slender, subcylindrical, belly flat; head rather indistinct from the 
neck, little larger, crown convex, narrow and pointed in front; tail short, 
near one eighth of the total, stout, tapering. Posterior upper maxil- 
lary teeth stouter. Mouth-cleft medium, slightly curved. Eye moderate, 
pupil subcireular (apparently a little oblong, erect). Rostral prominent, 
