REPORT ON THE MARSUPIALIA. 161) 



On the floor of the pouch there were four small conical elevations. These were very 

 slightly raised above the general surface, and were situated in the centre of the pouch. 

 On the summit of each elevation there was a minute aperture barely visible to the naked 

 eye, and on applying a magnifying glass and separating the lips of the opening with a 

 needle an exceeding minute teat was observed within. The conical elevations, therefore, 

 simply represented the integumental sheaths of the teats. 



In the description of the mammary organs of a Kangaroo by Mr. Morgan (Trans. 

 Linnean Soc, 1826), it is stated that the teats "after once being developed by protrusion 

 from their original situation in the substance of the gland, never again recede to their 

 former condition, but constitute permanent marsupial teats throughout the rest of life." 

 This statement confirms me in my opinion that the female Thylacine was in a virgin 

 condition. 



Sphincter marsupii (PI. IV. fig. 4, s.). Eeflecting the skin from the pouch a powerful 

 sphincter muscle is exposed. It is simply a portion of the panniculus carnosus. In front 

 the fibres decussate, whilst behind the two bands meet, and are inserted into the fibrous 

 tissue in front of the symphysis pubis. The inner margin of the muscle is contained in 

 the fold of integument bounding the pouch laterally, and is round and thick. Externally, 

 the fleshy fibres blend with those of the panniculus carnosus. 



Mammary glands. — The mammary glands could not be detected as structures distinct 

 from the superficial fascia in which they are placed. Within the area, surrounded by 

 the sphincter marsupii, several large lymphatic glands are embedded in the superficial 

 fascia at the back part of the pouch (fig. 4, l.<j.). 



Cremaster muscle 1 (fig. 4, c). This is a strongly-marked muscular band which 

 arises by two slips (l) from the anterior superior iliac spine, and (2) from the posterior 

 border of the transversalis muscle. Emerging from under cover of the internal oblique, 

 it passes downwards and inwards under cover of the aponeurosis of the external 

 oblique. It finally appears through the external abdominal ring, and passing under 

 cover of the sphincter marsupii, spreads out under the two nipples of its own side. It 

 was impossible to make out its precise connection with the teats. In the mammary 

 region a large branch of the deep epigastric artery is distributed, and a large nerve, the 

 genito-erural (fig. 4, g.c.n.) enters the substance of the cremaster muscle. 



1 In the male the cremaster muscle has the same origin. It envelopes the vas deferens, and spreads out upon the 

 tunica vaginalis. 



(ZOOL. CHALL. EXP. — PART XVI. — 1882.) Q 25 



