SYNOPSES AND DESCRIPTIONS. 17 



var. LA'iii AsrrATUM. 



Dipsas biscutata var. i.atifasi'ia Peters, L869, MB. Berl. Acad., S77. 



Rows of scales 21 — 22. Ventrals 20(> — 210. 13 — 14 brown bands on 

 the body; 5 — G on the tail. (From Peters.) l'nebla, Mexico. 



SlBON ANXULATUM. 



Coluber annulatus Lame, 1754, Mux. Ad. Frith: Tab. 8, frj. 2. 

 Sibon vxm i. Airs FUzinger, 1826, Neue Class. Rept.,60. 



Moderate, tapering to head and tip of tail; head large, distinct, depressed, 

 crown flattened, temples swollen; muzzle broad; tail medium. Eye mod- 

 erate, pupil oblong, erect. Posterior maxillary teeth longer, grooved. 

 Nasal in two parts; nostril lateral. Loreal present. Preoculars two; 

 upper large, reaching the top of the head, lower small in a notch between 

 the third and fourth labials, sometimes absent. Postoculars two, upper 

 large. Temporals 1+2. Labials eight, fourth and fifth in orbit, seventh 

 largest. Infralabials 10 (9 — 10), sixth largest. Submentals two pairs, 

 nearly equal. Scales smooth, in 23 rows (19 — 23), similar. Ventrals 

 188±. Anal bifid. 



Light reddish-brown, with a series of brown spots on each side of the 

 median line, which are alternated and form a zigzag line or opposed and 

 form transverse bands or rhombs. The number of spots varies much; in 

 the specimen before me there are fifty on the body alone. Flank mottled 

 with brown, lower portion with a series of spots alternating with those of 

 the dorsal. Head of the ground color, with a brown band behind the eye, 

 above the angle of the mouth. Belly uniform light color. Scales lustrous. 

 llab. Mexico to Brazil. 



Var. SEPTENTRIOXALE. 



Dipsas skitkntkionai.is Kennkott, 1859, U. S. and Mi.r. Bound. Sum., IF, pi. VIII, f. 1, />. 16. 



Preoculars three (2 — 3); upper large, reaching the top of the head: 

 lower very small. Scales in 19 — 23 rows, smooth. 



Yellowish white (brownish), with irregular transverse bands of brown, 

 which extend across the back to the ventrals. The bands vary much in 

 shape and size; the specimen at hand has thirty-eight in all. Old speci- 

 mens with darker colors. A band from the nostril through the eye to the 

 hinder labial. Head mottled or blotched with brown, sometimes with a, 

 shield-shaped spot on the occipitals. Hab. Texas to Central America. 



Mem. — vol. n — 2 



