could have had their tails broken at or soon after capture, assuming that none of the snakes was retained in captivity for an extended period.
Supralabials
The supralabials are either six (usually) or seven on a side ([Table 1]). When seven supralabials are present on either one or both sides, the addition results from one of the following conditions: a) 5 is divided to form 5 and 6 (N = 6); b) 2 and 3 form 2, 3, and 4 (N = 1); c) 5 and 6 form 5, 6, and 7 (N = 12); d) 4, 5, and 6 form 4, 5, 6, and 7 (N = 1); e) 1 and 2 form 1, 2, and 3 (N = 1); f) 1, 2, and 3 form 1, 2, 3, and 4 (N = 1); g) 2 is fused with the nasal, and 3 and 4 are reduced to granules (N = 1); h) type of addition unknown (N = 5).
Table 1. Variation in Number of Supralabials (N = 245) and Infralabials (N = 246) of Tantilla gracilis.
| Number of Supralabials | Number of specimens | Per cent of occurrence | Number of infralabials | Number of specimens | Per cent of occurrence |
|---|---|---|---|---|---|
| 6-6 | 221 | 90.2 | 5-5 | 5 | 2.0 |
| 6-7 | 10 | 4.1 | 5-6 | 4 | 1.6 |
| 7-6 | 10 | 4.1 | 6-5 | 5 | 2.0 |
| 7-7 | 4 | 1.6 | 6-6 | 229 | 93.1 |
| 6-7 | 1 | 0.4 | |||
| 7-6 | 2 | 0.8 |
In three of the four specimens with 7-7 supralabials, the type of addition is the same on each side, whereas the other specimen has a different type of addition on each side. Of the 23 examples for which the type of addition is known, 19 (82.6%) have the increase in number on the posterior half of the series.
In one specimen the third supralabial on the right is diagonally divided and the resulting upper part does not contact the edge of the lip; hence the specimen has 6-6 supralabials.
Infralabials
The infralabials are five, six (usually), or seven on a side ([Table 1]). When five infralabials are present on either one or both sides, the reduction results from one of the following conditions: a) 2 and 3 are fused (N = 3); b) 1, 2, and 3 form 1 and 2 (N = 6); c) 2, 3, and 4 form 2 and 3 (N = 3); d) 5 is separated from the edge of the lip by a projection from an adjacent infralabial (N = 1); e) 1, 2, 3, and 4 form 1, 2, and 3 (N = 2); f) type of reduction unknown (N = 4).
Of the specimens with 5-5 infralabials, two have the same type of reduction on each side, one has a different type of reduction on each side, and the type of reduction is unknown for the other two specimens.