270 PLECTOGNATHI. 



Family II GYMNODONTES. 



Body more or less short. Some possess the means of dilating an elastic 

 portion of the sesophagus, or an abdominal sac, with air : or this power may be 

 wanting. Bones of both jaws in the form of a beak, having a cutting edge, 

 and being covered with a layer of ivory-like substance, in which a median 

 suture may be present or absent. A spineless dorsal, anal, and caudal fin : 

 pectorals present : ventrals absent. Dermal covering modified into small or 

 large spines or laminae. Pelvic bones and air-bladder present or absent. 



This family is composed of several genera, most of which are exclusively 

 exotic, only a single species being found in our waters and that a rare visitor. 



Genus I Tetrodon, Linnceus. 



Leiosomus, Lagocephalus, Girrhisomus, and Psilonotus, Swainson. Kolacanthus, 

 Gray. Prilonotus and Anchisomus, Kaup. Tropidichthys, Bleeker. Promeco- 

 cephale, Bilobomyctere, Amblyrhynchote, Geneion, Gatophorhyne, Batrachops, 

 Rhynchote (Bibron) Dumeril. Rhynchotus, Apsicephalus and Brachycephalus, 

 Hollard. 



Bach broad or compressed into a ridge. A median suture in either jaw. Should 

 a conspicuous nasal organ exist, there may be two on either side in a papilla 

 (Tetraodon, Bleeker) ; or a single tubular one (Crayracion, Bleeker) ; or an imper- 

 forate one having a fringed edge, while the body of the fish is spinate (Chelonodon, 

 Miiller) : or a simple round cavity and the body of the fish smooth (Monotretus, 

 Bibron) : or two imperforate tentacles on either side (Arothron, Miiller) : or the 

 nasal organ may be inconspicuous, and the bach compressed into a heel (Anosmius, 

 Peters). Dorsal and anal fins with few rays. Body wholly or partially covered 

 with fine dermal spines, or such may be absent. There may be a more or less 

 distinct fold along the lower side of the tail and very apparent nasal organs 

 (Gastrophysus, Miiller) : or the fold be absent, but the body spinate and the 

 nasal organs very distinct (Cheilichthys, Miiller) : or the fold be absent and the 

 shin smooth (Leiosaccus, Giinther). A portion of the oesophagus dilatable and 

 capable of being distended with air. Air-bladder present and horse-shoe shaped. 



The Tetrodons in some portions of India are occasionally eaten by the lower 

 classes, but are said to occasion indigestion, so are usually avoided : while all 

 emit an odour the reverse of agreeable. The Burmese in some districts think 

 they are poisonous, while in other localities they attribute these deleterious 

 qualities to the gall-bladder. The Japanese eat one species as a means of 

 enabling them to commit suicide. The Andamanese eat them freely, appearing 

 rather to prefer them to other fish forms. In Batavia and Malayan countries 

 some are certainly poisonous, also in Egypt and at the Cape of Good Hope. 



In the Proceedings of the Linnean Society (v. no. 18, November, 1860), Mr. 

 Jamieson, of H.M.S. Winchester, gives an account of how, in Simon's Bay, two 

 Dutch sailors were poisoned by eating part of Tetrodon Guvieri. The liver of a 

 single fish was said to have been eaten, but both died in from seventeen to twenty 

 minutes. It was also stated that the cook who had fried the liver for the others, 

 and had eaten a small portion, exhibited no alarming symptoms. 



1. Tetrodon lagocephalus, Plate CXLVII. 



Seba, iii, pi. xxiii, f. 6 (young). Orbis lagocephalus, Willugh. Ich. p. 144, 

 t. iii, f. 2 ; Ray, Pise. p. 43. Ostracion, Artedi, Genera, p. 58, Synon. p. 86. 

 Globe diodon, Pennant, Brit. Zool. (Ed. 1776) iii, p. 132, pi. xx (Ed. 1812) iii, 

 p. 173, pi. xxiii. 



