172 
On the Respiratory Organs and Air Bladder 
[[June 
both mallei are at the same time gently depressed with the finger, upon the incudes . 
The anterior portion of the malleus , and the incus with its tendon, as far as its 
attachment to the stapes , are inclosed in a tendinous sheath, containing a quantity 
of gelatinous fluid : they have no muscles attached to them, and it is probable, 
therefore, that the slight motion which the malleus enjoys, through the medium of 
its articulation with the vertebra, is entirely regulated by the external coat of the 
air-bladder. 
The air-bladder of the Pimebdus Gag-ora, Pimelodus Bagharia , Silurus Singio, 
and Macropteronotus Magur, is placed behind the head, close to its articulation 
with the first vertebra, and in this situation is connected with the ossicula anditus , 
which are conspicuous, and present the same relative position as those of the 
Silurus Boa! is. 
In the P. Gagora there are two air-bladders lodged, one on each side, in an 
osseous cup, attached by a narrow neck to the body of the first vertebra, close to 
its junction with the cranium. The mouth of each of these cups is covered over 
by the common integuments, which are at this part extremely thin, and adhere to 
the surface of the subjacent bladder, presenting, when the latter is distended with 
air, an external elastic tumour, of an oval figure. The two air-bladders, which 
have no communication with each other, or with the alimentary canal, apparently 
derive their supply of air from a vascular tissue, placed between the two cups where 
they are attached to the spine : the external coat is of a thin texture, and argentine 
colour, and has a layer of fine adipose substance interposed between it and the in- 
ternal surface of the cup. 
The P. Bagharia ha3 also two air-bladders, which closely resemble the former in 
the argentine tendinous texture of the external coat, and in having no communica- 
tion with each other, or with the alimentary canal. They are situate, one on each 
side of the body, in a deep groove or furrow of the consolidated transverse processes 
of the cervical vertebrae, and are extremely small, in proportion to the bulk of the 
fish ; each of them, in an individual, weighing ten pounds, not exceeding a large 
garden pea in size : they are placed at the middle of the grooves, at about an equal 
distance from the common integuments (immediately behind the pectoral fins) and 
the vertebral column ; the space between each of them and the former being filled 
up with adipose substance, while that next to the spine is occupied by the malleus. 
In the Silurus Sbigio and Macropteronotus Magur , the air-bladder consists of two 
small pyriform bags, joined at their pointed extremities by an intermediate canal. 
It is situate across the spine j each of the pyriform portions being contained in a 
funnel-shaped case, projecting outwards from the side of the body of the first 
vertebra, and having its mouth covered over by the common integuments, as in the 
jP. Bagharia. The case is formed of bone above, and below by a tendinous mem- 
brane that extends across the inferior surface of the first vertebra, thus pi'otecting 
from the pressure the intermediate canal or isthmus by which the two pyriform 
poitions are united. A communication exists between it and the alimentary canal, 
by a small ductus pneumaticus from the intermediate canal to the esophagus. 
In the Bola Patna , Mystus Chetala , and Clupanadon Ilisha, there exists a more 
tin ect connection between the air-bladder and organ of hearing, than through the 
medium of the small bones above referred to. 
The air-bladder of the Bola Puma is of a pyriform shape, terminating behind iu 
a slender elongated process. From each side of this process an appendix arises by 
a minute origin, and proceeds by the side of the body of the bladder, gradually en- 
ar »mg in size, until it reaches its anterior extremity, opposite to which it divides into 
a number ot blind tortuous branches, that spread out upon the lower surface of the 
1 ney. Iwo ot tnese branches, which are considerably larger than the rest, follow 
Sln 8 l, b il courser one mounts over the bone corresponding: to the clavicle, 
.. a PP ears [externally under the thin integuments at the edge of the apertura branchi- 
11 e the other winds round the cavity in which the internal ear is lodged, and 
t, , s lts fellow of the opposite side, at its anterior part. This latter 
into o ** , • 1£ \° I ? e connec ted with the organ of hearing,) is dilated at its extremity 
„ cm ii -f a ® aa P e£ l hag, which is of a very thin delicate texture, and is placed in 
mp 1 P 1 , • 01 *° ssa 011 the external surface of the base of the cranium, having 
^ a - U i n se P tu ®> generally of a membranous nature, interposed between it and 
me pi ncipal ossiculum , or calcareous body of the internal ear. 
near th* tl !! s or & an . e xtends in length from the first vertebra to 
ing with Pnrh’oi 0t 1 i ai -. interiorly, it forms several chambers communicat- 
dinal sent..™ C behind is divided into two parallel cavities, by a longitu- 
P ; which, like that of the Trichopodus Colisa , is partly membranous. 
