Page 57. 
274 ON HALMATURUS LUCTUOSUS. 
The spleen is perfectly Macropine, being narrow and elongate, with 
a well-developed third lobule. 
The liver very closely resembles that of the different species of 
Macropus. In comparing the livers of different animals it is my habit 
to estimate by sight, and therefore only approximately, the bulk of the 
different lobes, and to write down the results in the form of a formula. 
Employing the divisions, so evidently natural, proposed by Prof. Flower, 
I commence by writing down the name of the largest lobe, after 
which the others in the order of their bulk, with symbols between each 
to indicate their relative size. Taking the liver-formula of Dorcopsis 
luctuosa as an example, it may be thus written, 
L.L. 2>C. 4>R.C. $>Sp.>R.L. 2>L.C. ; 
and it reads as follows :—The left lateral lobe (.L.) is the largest ; it 
is twice the size of the caudate (C.), which is half as large again as the 
right central (R.C.), which is half as large again as the Spigelian(Sp.), 
which is larger (very little) than the right lateral (R.L.), which is 
twice the size of the left central (L.C.). 
The similarly constructed formula of Macropus melanops is 
L.L.=C. 2>R.C. $>R.L. 3 >Sp. 3>L.C., 
and of Halmaturus derbianus 
L.L. 1>C=R.C. $>Sp. $>R.L. 2>L.C.: 
they show how great a similarity there is between the different mem- 
bers of the family Macropodide. 
The gall-bladder is situated in the deep cystic fossa; and the um- 
bilical fissure is not deep. The Spigelian lobe has its apex directed 
vertebrally and resting on the left lateral lobe, as in Macropus; no 
secondary lobules are connected with it. 
There is a peculiarity in the liver of the specimen of Dorcopsis 
luctuosa under consideration, which may be individual, or it may be 
characteristic of the species, genus, or subfamily; at all events, I have 
not seen it in any other mammalian animal. Looking at the diaphrag- 
matic surface of any multilobate liver, the lateral margins of the mass 
formed by the right and left central lobes are always seen to overlap, 
to a greater or less extent, the lateral lobes in an imbricate manner. 
Similarly the right lateral lobe overlaps or covers the caudate. In the 
livers of Macropus and Halmaturus which I have by me, this conforma- 
tion is strictly maintained. But in Dorcopsis luctuosa the caudate 
lobe overlaps the right lateral lobe (instead of being situated on its 
abdominal surface), in such a way that the last-named lobe is only 
seen between the right free edge of the right central lobe and the left 
free edge of the caudate. This condition is not brought about by any 
post mortem change in the position of the lobes, because the right lateral 
fissure is not so deep as to separate them at their vertebral extremity. 
