Family XII. Ophiocephalidæ.
(Cell-throats.)
These are fresh-water fishes, all inhabiting with one exception (an African species) the rivers of India. They are chiefly interesting because they possess certain peculiarities of internal structure, which distinguish them from all other fishes, and which are connected with habits and powers no less anomalous. The bones of the throat (or pharynx) are divided into small thin plates more or less numerous; and these form, by their frill-like undulations and contortions, intercepting cells, in which water can be retained, and whence it can flow forth upon the gills and keep them moist for a long time, when the fish is on the dry land. By this structure the members of the Family are enabled to crawl from the rivers and ponds which they usually inhabit, and migrate to others at a distance; or, as some suppose, hide themselves in holes in the muddy banks, during the season of drought, waiting for the return of the periodical rains to restore them to activity. It is affirmed by persons of veracity who have lived long in India, that in ponds which perfectly dry up, the bottom being hard and cracked, fishes are found a few days after the commencement of the rainy season, though no rivers or brooks flow into them. The size of the newly found fishes will scarcely admit the explanation which has been suggested of this phenomenon, viz., that they are just hatched from ova which had been deposited in the mud
