68 Mr. Morgan's Description 



making those dissections of which I have now to detail the 

 results. 



' Commencing the dissection upon the superficial covering of 

 the abdomen, and having removed the common integuments of 

 that part, it will be found, that a layer of panniculus carnosus of 

 extraordinary strength and thickness is spread over the whole 

 of the anterior and lateral parts of the abdominal parietes, con- 

 nected closely by dense cellular membrane to the subjacent 

 abdominal muscles, except at the part where the pouch is in- 

 terposed between them ; here it is in like manner connected to 

 the anterior surface of the pouch itself. The fibres of this 

 muscle are arranged in a double order, an indistinct laj'er pass- 

 ing transversely, the stronger and more numerous passing in a 

 perpendicular direction from the thorax to the lower part of the 

 abdomen, surrounding in their descent the mouth of the pouch, 

 to which they form a sphincter, and terminating by sending off 

 a narrow slip over the fore-part of the pubis, to be attached to 

 the sphincter muscle of the vagina. The action of this part of 

 the muscle, therefore, would operate in drawing the external 

 opening of the vagina forwards and upwards over the symphisis 

 pubis, and would thus approximate the external organs of gene- 

 ration to the mouth of the pouch (^aZ>. 4.y". a.). 



Whether this approximation takes place in the living animal 

 at the time the young is removed from the cloaca to the nipple 

 has not yet been clearly ascertained ; but if such were proved 

 to be the case, it is obvious that the action of these descending 

 muscular fibres must be mainly instrumental in bringing these 

 parts more nearly together. 



The panniculus carnosus being entirely removed, the struc- 

 ture and connections of the pouch were clearly exhibited. The 

 bag is simply formed of a fold or duplicature of the common 

 integument, which, as already stated, is attached before to the 



panniculus 



