———— tay 
of the Mammary Organs of the Kangaroo. 71 
at the point of its insertion ; while those which are attached to 
the inner side of the tendon are continuous with another layer 
of muscular fibre, which arises from the whole extent of the 
concave anterior surface of the bone, from its superior extremity 
to its base, passing transversely inwards, to be inserted into the 
posterior surface of the tendon of the external oblique muscle, 
along the linea alba. 'Fhis transverse muscle may be considered 
as part of the anterior rectus, with which it is continuous, and has 
no connection with its fellow on the opposite side, except by the 
intervention of the tendon of the two oblique abdominal muscles ; 
since a tendinous septum, behind the linea alba, is interposed 
between the points of their insertion. n 
We are however informed, in an account of the anatomy of 
these parts published in the Philosophical Transactions by Sir 
Everard Home, in the year 1795, that a transverse and conti- 
nuous layer of muscle is stretched between the two bones,—an 
arrangement of structure which | have not been fortunate enough 
to meet with in my dissections of these parts. And we are further - 
assured, that this transverse muscle actually performs the um 
of a sling, by which the mamma is supported. 
T confess that I am at a loss to account for the cause ih 
has given rise to this mistake in the dissection of a recent sub- 
ject; more particularly as that dissection was made by an indi- 
vidual whose character as a comparative anatomist has been 
held in high estimation. 'The author may possibly have met 
with a singular variety of formation in the animal which was 
submitted to his inspection, and which may account for the 
different results of our dissections; but l consider it almost 
impossible that he can have met with so great a deviation from 
the natural form and structure of this part, as to justify him in - 
ascribing to these muscles the use he has assigned to them: 
for their use is obviously that of moving the superior extremities 
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