THE MANDIBULAR AND HYOID MUSCLES OF MAMMALS. 581 
catory muscles and the intermaiidibiilaris are continuous vvitli 
one another and lie internal to the third division of the fifth 
nerve ; the upper limit of the cell column lies below the 
Gasserian ganglion. 
In a 5J mm. embryo (fig. 45) the Anlage of the masticatory 
Fig. 66. 
muscles spreads laterally in front of the third division of the 
fifth nerve, so that the nerve passes down behind the Anlage ; 
whilst the primitive position of nerve and muscle Anlage is 
preserved lower down in the region of the intermandibularis. 
In a 7 mm. embryo the Anlagen of the masticatory muscles 
and intermandibularis separate from one another. The first 
branch of the third division of the fifth nerve to be given off 
is the buccal, which runs forward above the Anlage of the 
masticatory muscles. The rami medialis and lateralis are 
formed in an 8 mm. embryo, passing respectively inwards and 
