3830.^ 
of certai n Fishes of the Ganges. 
173 
and partly composed of the spines that sustain the anal fin. These spines are 
long, hollow, cylindrical bones, and are connected by the internal lining coat of the 
bladder, reflected on both sides over their whole extent of surface. The lateral 
muscles forming the walls of the cavity are very thin, and send off from their 
lower part small slips of muscles that are inserted into the membrane between 
the spines, by which means the septmn can he expanded somewhat in the manner 
of a fan. A free communication exists between the two sides of the organ, through 
a number of foramina in the membrane connecting the spines, and anteriorly be- 
tween one of the chambers and the esophagus, by means of a round opening, 
wide enough to admit the point of the little finger. From the anterior part of the 
organ a canal proceeds upon the inferior surface of the cranium, as far as the 
cavity containing the internal ear, opposite to which it terminates in a blind extre- 
mity. It consists of a deep furrow on the external surface of the base of the 
cranium, covered below by an elongation of the external coat of the bladder, (hear- 
ing some analogy in its structure to the eustachian tube of the higher orders of 
animals;) and like the corresponding part in the liola Pania, is separated from the 
principal ossiculum of the internal ear, by a septum so thin and delicate that the 
slightest touch with a pin is sufficient to rupture it 1 . 
This air-bladder of the Clupanadon Ilisha is long, narrow, and pointed at both 
extremities, as in the genus Clupea. From its anterior extremity two very minute 
ducts arise, and proceed along the inferior surface of the cervical vertebrae and 
posterior part of the head, to terminate in two small air-bags, situate one on 
each side of the cranium. These ducts, when divided with the knife, present open 
mouths, scarcely large enough to admit the point of a fine bristle : they are semi- 
transparent, and bear a striking resemblance, both in structure and appearance, to 
the membranous semi-circular canals of the internal ear. The small bags to 
which they lead, are lodged in two cavities of a corresponding size in the substance 
of the osseous walls of the cranium, in which situation they are entirely conce ded 
from view. Each bag may be described as consisting of two portions : the first 
has a horizontal position, and somewhat resembles a French bean in figure ; the 
second is pyriform, is situate above the first portion, and is united to it at nearly 
a right angle. These bags have very thin septa interposed between them and the 
ossicula of the internal ear, and differ considerably in texture from the organ in 
the abdomen ; their external tunic being thin, and of a silvery appearance, while 
that of the latter is thick, and of a dark red colour, presenting a smooth internal 
surface, like that of a serous membrane. 
§ On the Anatomy of the Cuchia. 
The Cuchia, an animal generally regarded as a species of eel, is entirely des-> 
titute of tins, and presents, in the structure of its organs of respiration and circula- 
tion, some remarkable peculiarities, which would lead us to place it between the 
class of reptiles and that of fishes. It is common throughout the south-east 
parts of Bengal, especially in the vicinity of D,haca, where it is generally found 
lurking in holes and ci*evices on the muddy banks of marshes and slow-running 
rivers. Hamilton, viewing its single external spiracle or branchial aperture below 
the throat as a generic character, has assigned a place to it under the genus U?ii- 
hranchapertura of Lacepede, (the genus Synbranckus of Bloch,) and has given 
an accurate description of it in his excellent work on the fishes of the Ganges 2 . 
1 In tills species there is a cavity on each side of the head, corresponding to the 
tympanum of other animals. It is of an oval figure, and is covered externally by the 
common integuments, which are of a smooth shining appearance and destitute of 
scales. It is found to contain a quantity of gelatinous fluid, and has a thin cartilagin- 
ous plate imbedded in the latter on the one side, and attached to the portion of skin 
analogous to the membrana tympani, by a small hook-like process on the other. It 
leads to a small foramen on the side of the cranium. This foramen corresponds to the 
fenestra rotunda of Mammalia ; and is filled up by a thick membrane that separates 
the cavity of the tympanum from the ossicula , and the membranous semi-circular 
canals of the internal ear, 
2 This fish I found in the rivers and ponds of the south-east parts of Bengal. It 
is said to grow to two feet in length and six inches in circumference : hut those that I 
have seen were shorter and thinner in proportion to their length. Europeans eat the 
Cuchia as an eel : but the natives reject it, and imagine that its bite is fatal to cattle, 
although less powerful on the human kind; a supposition highly improbable. The 
whole form of the animal, having no vestige of a fin, resembles strongly a serpent. This 
fish is cylindrical, devoid of scales, and lubricated with slime. The colour above is dark 
green, below a dirty pale red : on every part are scattered small round black spots, and 
short yellowish lines. Two parallel pale lines run forward from the shoulders, aud at 
