of the Mammary OrgaJis 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. This 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. 



•! 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 1 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 office 

 of a sling, by which the mamma is supported. 



T confess that I am at a loss to account for the cause which 

 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 I 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 

 i .;.:; . of 



