The dorsal end of each cartilage is connected with the ear-capsule and is ossified to form the malleus; the ventral ends meet each other in the region of the mandibular symphysis, and are usually regarded as undergoing ossification to form that portion of the mandible which contains the incisor teeth.

The intervening part of the cartilage disappears; the portion immediately adjacent to the malleus is replaced by fibrous membrane, which constitutes the sphenomandibular ligament, while from the connective tissue covering the remainder of the cartilage the greater part of the mandible is ossified.

Then it grew longer and stronger, and acquired muscles capable of closing the developing jaw.

[1] In some extinct mammal groups like eutriconodonts, Meckel's cartilage still connected otherwise entirely modern ear bones to the jaw.

[2] This article incorporates text in the public domain from page 66 of the 20th edition of Gray's Anatomy (1918)