SUPPLEMENT ON LOPHOBRANCHII AND PLECTOGNATHI. 579 



formed by a swelling of the skin, in some under the belly, in 

 others under the base of the tail, and which divides to allow 

 the little ones to come forth alive, and already sufficiently 

 developed to provide for their own necessities. 



Of the next order Plectognathi, family Gymnodontes, 

 the genus Diodon is deserving of some observations in 

 addition to the text. 



The diodontes live on Crustacea and fueus. Their flesh is 

 generally mucous, and in no great estimation. They have the 

 power, as stated in the text, of swelling themselves out by 

 swallowing air, and filling their stomach with this fluid. 

 When they are thus inflated, they tarn upside down ; their 

 belly comes uppermost, and they float upon the surface of 

 the water, without being able to direct themselves. This 

 proves a means of defence to them, because the spines 

 with which their skin is furnished are then erected on all 

 sides. 



From the faculty they possess of distending their bodies 

 with air, these fishes have received in France the vulgar 

 names of boursonjius, which means bloated or blown up, 

 our balloon-fish ; and orbes, from the globular form which they 

 assume. That of diodon comes from the number of their 

 teeth, which it expresses in Greek, (Stc, two; and 6ovg, 

 tooth.) 



The species of this genus live in the seas of warm climates ; 

 we are in possession but of few details concerning each of 

 them ; but we shall examine the most important, observing, 

 however, at the same time, that very considerable confusion 

 predominates in their determination. 



The diodon Atinga, inhabits the seas of India, America, 

 and South Africa. It is found in abundance between the 

 tropics, and in the neighbourhood of the Cape of Good 

 Hope. It feeds upon small fishes, Crustacea, and testacea, 

 whose calcareous envelope it easily breaks by means of its 



p p 2 



