340 MR. F. DAT ON THE GEO&EAPHICAIi 



certainly sucli an organ, being almost incapable of expansion, would 

 scarcely be of mucb service as a compressible float. 



These fishes are generally well provided with weapons of offence^ 

 or defence ; they have mostly strong dorsal and pectoral spines, 

 often serrated and witli which they can inflict dangerous wounds. 

 This spinal armature is invariable in the marine and estuary 

 forms, as there they are most called upon to resort to offensive or 

 defensive measures. The auditory apparatus is more developed 

 in the inland genera, where, instead of having to battle for 

 their existence, they become the tyrants of the waters they in- 

 habit. 



Whether any East-Indian genera of Siluroids possess a distinct 

 poison-apparatus or gland connected by a dnct to a wound-in- 

 flicting-spine has not as yet been proved. But that most dangerous 

 symptoms are occasioned by their dorsal and pectoral spines, is 

 known not only to men but even to the lower animals. 



On June 18th, 1869, 1 was present in Burma when the famous 

 "Een-gay-gyee lake was fished, which is done by placing a stationary 

 weir across the water (which is a sort of river encircling an island) ; 

 and a movable one is with great labour dragged up to it by large 

 gangs of men, whose labours are continued for months. The final 

 point had now been reached ; and all round this enclosure nets 

 were reared to about ten feet above the water to prevent the fish 

 escaping", and which the captives, wild with alarm, were trying to 



^ La-ws baye been enacted in seyeral countries rendering it penal to bring 

 these fishes to the markets for sale with their spines intact. Omitting any con- 

 sideration of the state of the health of the indiyidual wounded, we find fishes 

 occasion three distinct Tarieties of wounds : — 



a. Punctured wounds inflicted by a spine destitute of a poison-gland or duct, 

 as seen in the European Weevils (Trachinus) or the East-Indian Folr/acanthus. 

 But as distinct irritating efiects extend for some distance from the wounded 

 spot, and remain for a considerable period, it seems questionable whether some 

 mucous or other substance causing these symptoms may not be present on the 

 spine. 



/?. Lacerated wounds, such as may be caused by the dorsal or pectoral spines 

 of Siluroids or the serrated spine on the tail of the Skates. In these cases also 

 irritation may be occasioned by some mucous secretion. 



y. Foisoned wounds. The Siluroid Thalassofhryne has been shown to have a 

 distinct poison-gland leading up a canal existing in a serrated spine by which 

 the wound is inflicted (Giinther, P. Z. S. 1864, p. 155). The Synanceia verrucosa 

 has also been shown to have a tube at each of its dorsal spines and a poison-gland 

 at its base. The wounds, as might be anticipated, are very Tenomous. 



* Salt for preserving them had not arriyed. 



