On harelip and cleft palate

by William Rose

Hence the dental formula in cases of alveolar harelip will vary as follows:

In tetraprodontous jaws—

CI₂=I₁I₁=I₂C,

or

C=I₁I₁=C;

in hexaprodontous jaws—

CI₂=IₐI₁I₁Iₐ=I₂C,

or

C=IₐI₁I₁Iₐ=C,

where Iₐ represents the accessory incisor, the other letters as on p. 51. The former of each of these pairs of formulæ represent the mesognathion and lateral incisor as present, the latter as absent.[59]