556 AL TELS. [VoL. XII. 
In specimens of from 10 mm. to 12 mm. in length the four 
divisions of the levator maxillae superioris are directly con- 
tinuous with the adductor mandibulae, their tendons, found in 
the adult, not yet having been formed, or at least not being 
distinguishable. The first and second divisions appear as a 
single muscle, connected with both the inner and outer divi- 
sions of the adductor, and arising from the front edge of the 
median process of the metapterygoid or from the upper sur- 
face of that bone near the process, the attachment to the 
hyomandibular and the position internal to the levator arcus 
palatini not yet having been acquired. The third division of 
the levator is well developed and arises in connection with the 
first and second divisions, but from the inner division only of 
the adductor. It extends forward under the eye and is either 
attached to the upper surface of the palatine cartilage or 
vanishes in the general tissues above it, having no visible 
attachment. No trace was found at this age of the fourth 
division as a separate muscle. 
ce. Levator Arcus Palatini. 
This muscle (Lag, Figs. 30, 31, and 36, Pls. XXVI, XXVII, 
and X XIX), called by McMurrich the first division only of 
the levator arcus palatini, is a stout muscle lying in origin 
and insertion internal to the plane of the median, dorsal 
process of the metapterygoid. It has in its upper part a 
strong, median, longitudinal aponeurosis, which extends into 
the muscle from its origin and front edge for about two thirds 
the length and breadth of the muscle. From this aponeurosis 
all the fibres of the inner portion of the muscle arise, and those 
of the outer in great part. 
The most anterior fibres of the muscle belong entirely to 
the outer of these two portions. They are distinctly marked 
off on the surface of the muscle (Fig. 36) from the remain- 
ing fibres of the outer portion, and have their origin from 
the lateral and front edge of the postorbital process below the 
dermal postfrontal bone and anterior to the lateral wing of the 
parasphenoid. They run almost vertically downward, bellying 
