THE MANDIBULAR AND HYOID MUSCLES OF MAMMALS. 587 
19 mm. embryonic pig ; the stage of development is a little 
less advanced than a 13 mm. rabbit embryo. MeckePs car- 
tilage is a slightly curved rod of pre-cartilage; its hinder 
portion and the Anlage of the mandible, though present, had 
Fig. 72. 
not sufficiently clear outlines to be modelled. The Anlage of 
the ala temporalis is present ; those of the ala orbitalis, orbito- 
parietal commissure, parietal-platte, and processus alar is, 
are not yet formed. The Anlage of the masticatory muscles 
forms a continuous mass, approximately /y-shaped, with an 
apex just beneath the ala temporalis, and having an upward 
projection on the outer side of the Gasserian ganglion. The 
