Lacunal scales are those

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

that form the inner border of the

loreal pit The loreal pit is the deep depression, or fossa, in the loreal area on either side of the head in pit vipers (crotaline snakes). The area is located behind the nostril and in front of the eye, but below the line that runs between the centers o ...

in crotaline snakes. Usually, these scales are large and also curve outward to form the outer border of the pit. In most cases the pit opening is triangular with one apex pointing back towards the eye. It is bordered above, below and in front by one or more supralacunals, sublacunals and prelacunals respectively.Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. 2 volumes. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. .

References

{{Reflist Snake scales