226 MR, F, B, BEDDARD ON THE [Feb. 4, 
called ‘diaphragm’ (‘diaphragme thoraco-abdominal,’ Sappey ; 
‘diaphragmite thoraco-abdominal, Milne-Edwards) is a more 
or less aponeurotic fibrous membrane, continuous with the 
ventral edge of the median dorsal septum and suspended by it, 
like the roof of a tent, across the thoraco-abdominal cavity. In 
the middle line, this oblique septum slopes downward and forward 
to the dorsal and anterior face of the pericardium, with which its 
fibres become firmly connected on their way to their attachment 
to the sternum. From the median line, the two halves of the 
oblique septum slope laterally and ventrally until they attach 
themselves to the parietes of the abdomen behind, to those of the 
thorax more anteriorly, and to the margins of the sternum in 
front.” 
In fact, if we make a transverse section through a Duck or most 
other birds at the level of about the middle of the sternum, the 
appearances will be such as are diagrammatically represented in 
the accompanying drawing (fig. 1, p. 227). Four membranes are 
there visible—the intestines being left out of consideration for the 
purposes of simplification, and as not germane to the structures 
at present under discussion. The first of these is the falciform 
ligament, which divides the lobes of the liver and is attached below 
to the middle line of the sternum. Then there are the oblique 
septum (0.S.), attached below to the sternum laterally, and above 
to the parietes; and finally the horizontal septum (A.S.), which 
floors the two cavities containing the liver-lobes. 
This arrangement, however, does not hold good for a number of 
Passerine birds; and it is possible—though I am not yet in a 
position to make a definite statement about the matter—that the 
arrangement which I am about to describe as characteristic of 
many Passerines will be found to be distinctive of the group. 
I commence with a somewhat detailed description of the oblique 
septa of a Crow (Corvus capellanus) (see fig. 2, p. 227). As I have 
dissected three examples of this bird, the following description 
will probably be found to be free from any record of abnormal 
conditions. 
The right lobe of the liver is considerably larger than the left, 
and extends some way beyond the margin of the sternum, in fact 
about as far as to the end of the posterior intermediate air-sac. It 
is separated from the liver-lobe of the left side as usual by a 
vertically directed septum, the umbilical or falciform ligament ; 
this falciform ligament is attached to the ventral parietes for a 
distance of about an inch—from the posterior end of the sternum 
to a point rather in front of that which corresponds to the 
posterior margin of the liver. Anterior to the posterror edge of the 
sternum, the falciform ligament is not attached to that bone; tt 
becomes fused with the two oblique septa, forming a roof over the liver- 
lobes in this region, which is separated by a wide interval from the 
internal surface of the sternum. 
The oblique septa are closely attached for a considerable distance 
to the liver-lobes, the adhesion being certainly not pathological. 
