170 OSSEOUS, MUSCULAR, AND NERVOUS SYSTEMS 
aponeurosis covering the rectus muscle, nearly midway be^ 
twixt the sternum and pubes. 
Another short but powerful muscle arises from the whole 
inner surface of the squamous process of the scapula, and 
is inserted most extensively into the broad inner surface of 
the OS humeri ; and close to it is a muscle having a similar 
origin, but is inserted into the first rib *. The muscles con^ 
necting the dorsal portion of the scapula with the spine, 
and the former with the os humeri, are tolerably regular, 
and at least as numerous as in any of the Mammalia. The 
extensors of the fore-arm seemed to me powerful : the same 
observation is applicable to the other muscles of the fore^ 
arm and leg, the extent and nature of whose motions may 
be judged of, by observing the bones, and, more particu- 
larly, the development of the radius and tibia. 
The sterno-mastoid is fixed into the small horizontal 
bone, which M. Geoffroy calls the acromial process, and 
into the horizontal branch of the clavicle immediately con- 
nected with it. It thus becomes either a sterno-mastoid, 
cleido-mastoid, or scapulo-mastoid muscle, according to the 
view adopted relative to these bones : at the same time, the 
omo-hyoideuSy which is much more developed proportion., 
ally than in the human subject, arises from the scapula, 
close to where it is connected with the horizontal branch of 
the clavicle, and following the regular course of the muscle 
is inserted into the os hyoides. 
These are all the details relative to the muscles with 
which I have thought fit to trouble the Society. 
The brief account I propose giving the Society of the 
Nervous System, cannot be expected to be either minute 
* From the number and strength of the muscles coimected with this 
anomalous bone, may be judged its importance in the movements of the 
shoulder, and its influence even over the thorax itself. 
