It has been already pointed out that they commence at about the same spot in the lip margin as ordinary harelip, and thence run upwards and outwards clear of the ala nasi towards the centre of lower eyelid, following along the line of the naso-orbital fissure. Such a condition, coupled with the developmental facts already mentioned, viz. the existence of four segments in the intermaxilla and their relations to the internal and external nasal processes, suggests the following conclusions: 1. That the situation of the cleft in the lip margin is in all probability between the internal nasal and maxillary processes. The truth of this proposition depends on whether or not the external nasal process has any share in the formation of the lip. His, in his diagrams (Fig. 30), seems to indicate that it does not, whilst Biondi[61] claims that it does. The fact that these facial clefts commence at about the same spot in the lip margin as do the clefts in harelip seems distinctly to point to the conclusion that the superficial portion of the external nasal process is limited to the development of the ala nasi, and of the soft parts immediately around it. And this opinion goes far to explain the dimpling of the skin around and the consequent definition of the ala nasi. 2. That the situation of the cleft in the alveolus is between the meso- and exo-gnathion, so that the first tooth on the outer side, if developed, will be the canine. 3. That the upper extremity of the cleft should typically be located at either the inner canthus or about the middle of the lower eyelid; but this is not always the case. The association with coloboma iridis is readily explained by an imperfect closure of the choroidal cleft which normally occurs at the lower and inner segment of the globe. _Median harelip_ in its two forms is readily explained. The true median cleft is due to the non-union of the two globular processes developed from the median portion of the fronto-nasal outgrowth. If prolonged between the bones, it occupies the position of the median inter-intermaxillary suture, and so passes between the two endognathia. The more serious and complete form is due to the non-development of the globular processes, and hence absence of the central portion of the lip, the endognathia, and of the ethmo-vomerine plate. The contour and size of the alæ nasi in pictures of this deformity suggest strongly that the external nasal processes are developed, but no record of the dentition of these rare cases is to be found. _Macrostoma_ is due to the non-union of the maxillary and mandibular processes, or possibly in some instances to the imperfect development of the former.