1896.] ANATOMY 0¥ PETBOGALE XANTHOPUS. 699 



border into the cartilages of the second, third, and fourth ribs. 

 It has a few indistinct intersections. 



The Pyramidalis rises from the inner side and tip of the mar- 

 supial bone, and from the fascia over the lower part of the rectus. 

 About midway between the pubes and xiphoid it blends with the 

 linea alba. 



The Supracosialis rises from the sternal ends of the cartilages of 

 the 3rd, 4th, and 5th ribs, and is inserted into the first rib just, 

 external to the attachment of the rectus. It is well marked, and 

 continues the plane of the external oblique, lying between the 

 rectus and the pectoral. 



The Quadratits lumhorum is present, but is extremely ditHcult to 

 separate from the erector spina;. 



The Psoas parvus is very large, and rises from the bodies of all 

 the lumbar vertebrae except the last ; it is inserted into the pro- 

 minent ilio-pectineal eminence. 



The Psoas magnus is smaller than the last, and rises from the 

 transverse process and side of the body of the last lumbar vertebra, 

 as well as from the anterior part of the sacrum ; it joins the 

 iliacus to form a very broad ilio-psoas, which is inserted into the 

 flat lesser trochanter. 



Muscles of the Tail. 



These muscles are by no means easy to distinguish one from the 

 other, but the following seems tlie most satisfactory division. 



The Extensor caudce externus rises from the accessory processes 

 of all the lumbar vertebrse, from the sacrum, and from the caudal 

 vertebra} nearly as far as the middle of the tail. The tendons, 

 which are very long, are inserted into the transverse processes of 

 the caudal vertebrae, those which rise most anteriorly being inserted 

 first. Meckel ' describes this muscle as being distinctly divided 

 into two . in the Kangaroo, but I was unable to make out the 

 division satisfactorily. 



The Extensor caudce inter7ius is fleshy, and rises from the spines 

 of the sacral and caudal vertebrae; short tendons pass to the 

 transverse processes of the vertebrae close behind. 



The Abductor caudai externus rises from the ischium, and is 

 inserted into the transverse processes of the 5th, 6th, and 7th 

 caudal vertebrae. 



The Abductor cavdm intemus is simply a continuation of the 

 intertransversales muscles. 



The Flexor caudai externus conies from the ventral surface of 

 the sacrum and tail, and is inserted into the ventral surface of the 

 transverse processes by long tendons, which are arranged in the 

 same manner that was noticed in Sjphincjurus ' — that is to say the 

 most superficial tendons are first inserted, and the deeper ones 

 reach the surface round the inner side of these. 



^ ' Anatomie oomparee,' vol. ^i. p. 177. 

 ■■' "Myology of BodenU," P.Z.S. 1894, p. 279, 



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