The

callionymus, also, has the gall-bladder close to the liver, and in
no other fish does the organ attain so great a relative size. Other
fishes have the organ close to the gut, attached to the liver by
certain extremely fine ducts. The bonito has the gall-bladder
stretched alongside the gut and equalling it in length, and often a
double fold of it. others have the organ in the region of the gut;
in some cases far off, in others near; as the fishing-frog, the elops,
the synagris, the muraena, and the sword-fish. Often animals of the
same species show this diversity of position; as, for instance, some
congers are found with the organ attached close to the liver, and
others with it detached from and below it. The case is much the same
with birds: that is, some have the gall-bladder close to the
stomach, and others close to the gut, as the pigeon, the raven, the
quail, the swallow, and the sparrow; some have it near at once to
the liver and to the stomach as the aegocephalus; others have it
near at once to the liver and the gut, as the falcon and the kite.