586 
F. H, EDGEWORTH. 
portion; it arises partly from the tendon of the tensor veli 
palatini, partly from the outer surface of the auditory capsule. 
The external pterygoid arises partly from the external 
surface of the ala temporalis and partly from the palatal 
portion of the common Anlage of the palate and pterygoid 
bones. The temporal arises by two heads, from the lamina 
Fig. 71. 
ascendens alae temporalis and from the Anlage of the parietal 
bone. The masseter and zygomatico-mandibularis, not yet 
separated, are continuous dorsally with the temporal. 
In a 33 mm. embryo (fig. 54) the zygomatico-mandibularis 
and masseter have become separated. The palatine and 
pterygoid bones have ossified, aud one head of the external 
pterygoid arises from the palate bone. 
Figs. 70 and 71 represent a model made from sections 
passing through the Anlage of the masticatory muscles in a 
