Chambers's Journal of Popular Literature, Science, and Art, No. 684

With such a combination of the characters of land and water animals, it is little to be wondered at that the true position of the Mudfishes in the zoological scale should have formed a subject for much discussion. They appear, however, to be true fishes, and not amphibians, and they therefore may legally occupy a prominent position among the oddities of their class.

Other curious beings included among the fishes are the so-called Globe-fishes (Diodon, &c.), which derive their name from their power of distending their bodies with air at will; and their bodies being usually provided with spines, they may be judged to present a rather formidable front to any ordinary adversary, in their expanded condition. Then also we have the curious Trigger-fishes (Balistes), so named from the prominent pointed spine in front of the first of the back-fins; this spine firmly holding its erect position until the second spine or fin-ray be depressed, when the first spine is released by mechanism resembling that of the trigger of a gun. The obvious use of such an apparatus is clearly of a defensive kind; and it is remarkable to find a familiar mechanical appliance of man so accurately reproduced in the fish – or rather, vice versâ.