FLYING FISH. 
7 
ation of fishes, the possibility of their air-bladder acting subsidiarily 
to the branchiae, has not passed unnoticed by authors ; but I am not 
aware that this organ in the flying-fish has been pointed out as likely 
to assist the respiration of that animal out of the water. And yet 
I had once flattered myself with the belief that I had discovered its 
communication with the mouth under such circumstances of organ- 
isation as precluded any doubt of its aiding the function of aerial 
respiration. But I had only one opportunity of dissecting the animal 
when recently taken, and I dare not trust to a single observation. I 
would recommend however those, whose opportunities are frequent 
of possessing the flying-fish soon after death, to examine attentively 
the termination of its air-bladder at the pharyngeal bones. These 
bones, in all other fish * * which I have examined, are two in number, 
and much apart, their office being to assist deglutition and to shield 
the blood-vessels which ramify under them on their way to the 
branchiae. In the flying-fish their number and position is different, 
allowing the inference that their function is also different. They are 
in this animal four in number, two large and two small. The two 
former in close apposition are situated immediately above and behind 
the anterior orifice of the oesophagus, and are compressed by the 
latter, which are united to them by a strong elastic membrane. 
Muscles are attached to the larger bones so as to separate them by 
their contraction. The anterior termination of the air-bladder is at the 
posterior portion of the larger bones. The question to be determined 
is, whether the air-bladder has an orifice at this part, which is opened 
and closed by the separation and re-union of the pharyngeal bones. 
On the evening of the 4th March we passed the line, and on the 
following morning shortened sail, to pay the usual homage to Nep- 
tune, which being accomplished we proceeded on our voyage. 
j * Since my return I have examined a specimen of the Exocoetus Mesogaster, preserved 
in spirit, in which the two large bones were united, but there was an orifice between them 
and the small ones ; whether it led into the air-bladder or not I was unable to determine. 
The same specimen had only eight, instead of ten, rays to its branchiae. 
* B 4 
