618 Mr. W. H. Workman on the Funclions of the 
which is rigidly fused to the frontal bones of the skull; next 
I found the maaillary running along the edges of the pre- 
maxillary and incased in a blackish sheath, but not attached 
rigidly to it. This bone divides posteriorly, the maxillary 
portion running upwards to the frontals, where it is attached. 
The other part is continued by the zugal and the guadrato-jugal, 
this latter being attached to the quadrate which hes just 
beneath the ear-cavity. Now, by grasping the upper man- 
dible of a fresh specimen about the middle with my finger 
and thumb, and catching the maxillary at the fork with a 
pair of forceps, I found by moving the forceps I was able 
with very little force to push the maxillary forward, and so 
lift the anterior part of the upper mandible, as shown in 
the figure (p. 619), and also depress it by reversing the action. 
As to the muscles concerned in carrying out this move- 
ment, it will be seen from the account given by Hérissant 
how they act in birds generally, but an account of my 
own experiments may be of interest to the readers of 
“Phe: Ubis.t 
I made a number of dissections and found that the 
entotympanic muscle was the muscle that pulled forward the 
quadrate and pterygoid bones. This is Shufeldt’s * descrip- 
tion of it:—“ The entotympanic is a small, spindle-shaped 
muscle, which arises quite fleshy from the sides of the basi- 
sphenoid, and to a limited extent from the base of the rostrum 
immediately beyond it. As it passes backwards and down- 
wards, it rapidly contracts to form a double tendinous slip. 
One of these is inserted into a little spme-like process on the 
upper side of the shaft of the corresponding pterygoid, close 
to its quadratal articular end. The other is inserted into the 
quadrate itself, close to the pterygoidal articulation, and to 
its outer side. 
“When these muscles contract, they pull forward the 
quadrates and pterygoids, which latter, in pushing against 
the palatines, tend to raise the superior mandible.” 
Now I found, on carefully removing the pterygoideus 
* © Myology of the Raven,’ pp. 19, 20. 
