Observations on certain parts of the animal oeconomy. Inclusive of several papers from the Philosophical transactions, etc / by John Hunter ... With notes by Richard Owen.
- John Hunter
- Date:
- 1840
Licence: Public Domain Mark
Credit: Observations on certain parts of the animal oeconomy. Inclusive of several papers from the Philosophical transactions, etc / by John Hunter ... With notes by Richard Owen. Source: Wellcome Collection.
417/494 page 409
![other, nor anything relating to the animal ceconomy of fish in gene- ral. The first, or common animal part, is so contrived as to ex- ceed what was necessary for itself, in order to give situation, nou- rishment, and most probably the peculiar property to the second. ‘The last part, or peculiar organ, has an immediate connexion with the first, the body affording it a situation, the heart nourishment, and the brain nerve, and probably its peculiar powers. For the first of these purposes the body is extended out in length, being much longer than would be sufficient for what may be called its progres- sive motion. For the real body, or that part where the viscera and parts of generation lie, is situated, with respect to the head, as in other fish, and is extremely short, so that, according to the ordi- nary proportions, this should be a very short fish. Its great length, therefore, seems chiefly intended to afford the surface for the sup- port of the peculiar organ; however, the tail part is likewise adapt- ed to the progressive motion of the whole and to preserve the specific gravity ; for the spine, medulla spinalis, muscles, fin, and air-bladder* are continued through its whole length. Besides which parts there is a membrane passing from the spine to that fin which runs along the belly or lower edge of the animal. This membrane is broad at the end next to the head, terminating in a point at the tail; it is a support for the abdominal fin, gives a greater surface of support for the organ, and makes a partition between the organs of the two opposite sides. The Organs. The organs which produce the peculiar effect of this fish con- stitute nearly one-half of that part of the flesh in which they are placed, and perhaps make more than one-third of the whole animal. There are two pair of these organs, a larger and smaller, one being placed on each side. The large pair occupy the whole lower or anterior, and also the lateral part of the body, making the thick- ness of the fore or lower parts of the animal; and run almost through its whole length, viz., from the abdomen to near the end of the tail. It is broadest on the sides of the fish at the anterior end, where it incloses more of the lateral parts of the body, becomes narrower towards the end of the tail, occupying less and less of the sides of the animal, till at last it ends almost in a point. These two organs are separated from one another at the upper part by the muscles of the back which keep their posterior or upper edges ata considerable distance from one another; below that, and towards the middle, they are separated by the air-bag, and at their lower parts they are separated by the middle partition. They begin for- * [The Gymnotus electricws has two air-bladders, one of which, of an oval form and bilobed, is situated at the anterior part of the abdomen, beneath the ceso- phagus; the other is the elongated sac deseribed by Hunter, and extended through the posterior part of the body. In another species, the Gymnotus xqui- sabiatus of Humboldt, the posterior elongated air-bladder is wanting. ] 36](https://iiif.wellcomecollection.org/image/b33292292_0417.jp2/full/800%2C/0/default.jpg)
