180 ON THE ANATOMY OF THE KOALA. 



It is 2| inches long from its apex to the commencement of its duct 

 opposite the anterior margin of the left central lobe. The free part is 

 connected by a peritoneal investment to the sides of the cystic fissure. 



In a second liver of Phascolarctos examined (which, however, having 

 been extracted from a spirit-preserved animal, an adult $ , is not so 

 well preserved as might be wished) the same general features obtain. 

 The left lateral fissure, however, is less distinct, as is the caudate ; and 

 the left central lobe is smaller proportionally to the left lateral. The 

 Spigelian wants the 'pointed apex ; and the development of secondary 

 fissures seems to attain an even greater extent*. 



P. Z. S. 1881, The bile- and pancreatic ducts open into the duodenum 2| inches from 

 the pylorus. The pancreatic duct is dilated terminally into a vesicle, 

 which does not receive the bile-duct, the latter opening alongside the 

 former into the intestine. 



P. Z. S. 1881, The spleen, as usual in Marsupials, is somewhat triradiate in shape, 

 being broader and forked at one end, tapering and more pointed at the 

 other. Its greatest length is 2 5 inches. There is a lymphatic gland, 

 the size of a pea, outside each marsupial bone, and a pair of similar ones, 

 superficial, on the neck. The axillary glands are large. 



The heart is of the usual Marsupial type. The right auriculo-ventri- 

 cular valve in membranous, and nearly complete all round the aperture, 



P. Z. S. 1881, being largest on the right side. It is attached to two, or, in one of my 

 specimens, three columnce carnece, which also decrease in size from right 

 to left. On the side corresponding with the septum the valve is attached, 



* In Phalangista vulpina the right central lobe is also, as in the Koala, the biggest, 

 and very deeply divided by a cystic fissure. The gall-bladder, however, does not nearly 

 reach the margin of the liver ; the left lateral lobe is much bigger than the right 

 lateral, which is as large as the left central ; the caudate is quite free and narrow. 

 All the lobes are remarkably distinct ; and their margins are quite simple, with no 

 trace of any such fissures as obtain in the Koala. 



The liver of Cuscus maculatus is formed on a similar principle, though the right 

 central lobe is not bigger than the left lateral, and the gall-bladder reaches to the liver- 

 margin. All the lobes are simple. The caudate and Spigelian, though small, are 

 quite distinct. The livers of Belidens sciureus and B. breviceps, Acrobata pygmcea, and 

 Dromicia (nana ?), though differing among themselves considerably in the relative 

 degree of development of their constituent lobes, all agree in having a distinct and free 

 caudate lobe, as well as a Spigelian, and in no system of secondary sulci attaining any 

 degree of development. 



In Phascolomys wombat the left lateral lobe is the largest ; the right central is also 

 large ; but the left central is very small, as is the right lateral fissure. The umbilical 

 fissure is distinct, as is the cystic fissure, which allows the gall-bladder, which reaches 

 to the anterior margin of the liver, to appear superficially. There are no distinct 

 caudate or Spigelian lobes, though the former is indicated. There is a tendency 

 particularly on the left lateral and right central lobes, to develop accessory sulci. 

 As in the Koala, too, the small right lateral lobe is pointed below. 



