of the species is based on an adult male from 6 miles southeast of Tamazulápam, Oaxaca, México (University of Kansas Museum of Natural History No. 40143).

Scutellation.—Head shields normal; upper labials 7-7 (third and fourth entering orbit); lower labials 9-9 (1-4 in contact with anterior chin-shield, 4 and 5 in contact with posterior chin-shield); preoculars 1-1 and not in contact with frontal; postoculars 2-2; temporals 1-2-3, 1-2-3; nasals divided by a distinct groove below nostril and faint groove above; portion of rostral visible from above, one-third length of internasals; internasals pentagonal and one-half as long as prefrontals; parietal suture approximately as long as frontal; ventrals 178; anal divided; caudals 80. Scales in 21 rows at midbody and showing the following reduction:

2 + 3 (130)          8 + 9 (162)
             21 —————  19 —————  17 (178)
2 + 3 (130)          8 + 9 (152)

Coloration.—Dorsal ground-color light brown and extending onto edges of ventrals; transverse body blotches numbering 50, each 1½ to 3 scales long and separated by light interspaces 1½ to 2 scales long; blotches brownish black and extending onto second scale row; lateral intercalary spots forming dark smudges on rows 1 and 2. Top of head black, flecked with tan; nape cream, followed by dark band six scales long; dark nape stripe from posterior edges of parietals to first dark body band. Venter cream-tan; throat and labials cream; posterior margins of all upper labials and of lower labials 1-3 black-edged (Figure 1).

Size and Proportions.—Head and body 312 mm. long; tail 118 mm., amounting to 37.8 per cent of length of head and body.

Fig. 1. Dorsal and lateral views of the head of Tantalophis discolor (Günther). (KU No. 40143). × 7.

Variation.—Data on the syntypes of Leptodeira discolor furnished by J. C. Battersby give some indication of the variation in the species. Both are males, and they have 175 and 180 ventrals, 88 and 89 caudals, 1 preocular, 2 postoculars, 1-2-3 temporals, 7 and 8 upper labials, 9 lower labials. They have body lengths of 365 and 402 mm., total lengths of 509 and 555 mm., tail/body ratios of 38.0 and 39.4. They have 51 and 54 dark blotches on the body.

Skull.—The skull is typically colubrid and shows no modifications. The quadrate has both a median and a lateral depression, forming a strong lateral flange on the anterior edge; the columellar process is elliptical, and the supracolumellar crest is robust. The posteroinferior vomerine process extends directly posteriorly and then angles sharply posterodorsally, enclosing an elliptical vomerine fenestra. The lateral processes of the premaxillary are slightly pointed; the median spine is relatively thin and high. The pterygoids bear 23 and 21 teeth that decrease in size posteriorly; the transpalatine articulating process of the pterygoid is rounded, not robust; the lateral crest is high and moderately robust; the depression in the ventral surface of the pterygoid is moderate. There are 12 and 13 maxillary teeth that increase in size posteriorly; these are followed by a short diastema and two larger, solid teeth. The prediastemal teeth are slightly curved and slender. The maxillary is laterally compressed; the posterior knob is not robust; there is one foramen in the lateral face of the bone (Figure 2). The 10 palatine teeth are almost uniform in size; the dentary bears 19 teeth that decrease in size posteriorly.