538 MR. F. £. BEDDARD ON THD [Apr. 21, 
6. On the Anatomy of a Grebe (Achmophorus major), 
with Remarks upon the Classification of some of the 
Schizognathous Birds. By Franx E. Bepparp, M.A., 
F.R.S., Prosector to the Society. 
[Received March 17, 1896.] 
As so few of the Grebes have been dissected, I took the 
opportunity offered, by the death some months since of a specimen 
of &chmophorus major, to make some notes upon the principal 
viscera and muscles, which I now lay before the Society. 
As is well known, birds differ very much in the extent of a 
horizontal membrane which is attached laterally to the oblique 
septa and posteriorly and ventrally to the abdominal wall. This 
membrane has been variously termed ‘ Omentum,” “‘ Pseudepi- 
ploon,” and ‘‘ Horizontal septum.” When the abdominal viscera of 
the Grebe are exposed by cutting carefully through the body-wall 
at some distance behind the sternum, the cavity which contains 
them is seen to contain only the intestines. As is the case with 
many other birds, with many Passeres for instance, the duodenal 
loop is very extensive, reaching right to the end of the abdominal 
cavity. This cavity, containing the intestines, is shut off from the 
anterior part of the abdominal cavity by an almost vertical septum, 
which isthe reduced equivalent of the horizontalseptum. This septum 
cuts off from the intestinal cavity another cavity which incloses the 
gizzard and the liver, and is again divided into right and left halves 
by the falciform ligament. The right cavity thus formed contains 
as usual only the right Jobe of the liver. I should mention also, 
as a fact of some systematic importance, that neither the gizzard 
nor the entire extent of the liver is sheltered by the sternum; 
they lie nearly altogether behind it. In this particular Zchmophorus 
differs from Psophia, Cariama, and the Rallide; but the Grebe 
agrees with those birds as well as with the Ducks in the small 
extent of the horizontal septum. 
§ Myology. 
I have only made notes upon the more important muscles from 
a classificatory point of view. 
The arrangement of the tendons of the tensores patagii is 
characteristic. The tensor brevis is early divided into two separate 
tendons which run down the patagium to be inserted as usual on 
to the forearm. They do not, however, as in the majority of birds, 
form well-defined narrow tendons, but are thin and ill-defined 
sheets of tendon. The division which lies nearest to the humerus 
is particularly thin and difficult to delimit. The outer band has a 
thickened strand on the side nearest to the humerus; it thins off 
gradually on the outer side. The nerve to the hand passes under 
