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Family III. SILUKID.E. 



Margin of the upper jaw formed mainly by the premaxillaries ; 

 the maxilla rudimentary, often constituting the base of a barbel ; 

 no subopercle. The rayed dorsal fin or the adipose dorsal may be 

 present or absent. Skin scaleless, aud either smooth or covered 

 with osseous plates, or scattered tubercles. Air-bladder, when 

 present, either free in the abdominal cavity or more or less enclosed 

 in bone ; it communicates with the organs of hearing by means of 

 the auditory bones. Csecal appendages absent. 



The Siluroid, or scaleless, fishes are popularly termed Cat-fishes, 

 owing to most of them being provided with feelers or long barbels 

 arranged around the mouth. They mostly prefer muddy to clear 

 water, and the more developed the barbels, the more these fishes 

 appear to be adapted for an inland or muddy freshwater residence. 



The wider and deeper the rivers, the more suited they are for 

 the Siluridce, consequently the larger forms are comparatively rare 

 in the south of India, whilst they abound in the Indus, Juiniia, and 

 Ganges, also in the Irrawaddy and other Burmese rivers. 

 . Owing to their usual resort, these fishes appear to employ their 

 feelers in moving about in muddy places, and consequently have 

 less use for their eyes than forms that reside in clear pieces of 

 water. This is one reason why the size of the eye as compared 

 with the length of the head is much greater in the young than in 

 the adult. The eye in fact atrophies, it does not increase in size 

 in proportion with the remainder of the head. In some species, 

 the skin of the head passes over the eye without any trace of a 

 free orbital margin. 



In the genus Arius and some allied marine forms, the males 

 appear to carry the ova in their mouths perhaps until the young 

 are produced. 



Many of these fishes are credited with causing poisonous wounds, 

 and we frequently find such cases admitted into hospitals. The 

 injuries may be divided into two classes, (1) those in which the 

 wounds are of a distinctly venomous description, (2) those in which 

 the jagged spines occasion intense inflammation often of a dangerous 

 character. 



The respiration of these fishes is effected in two ways, and it may 

 be appropriate here to refer to the amphibious fishes of India, as 

 the Lalnjnntliid and Qphiocephalidai. Kespiration in fishes is 

 carried out normally, (1) by their using the air which is in solution 

 in the water to oxygenate 'the blood at their gills, (2) by taking in 

 atmospheric air direct, which is employed at a special organ, where 

 it oxygenates the blood, which can be returned for use into the gen- 

 eral circulation without going through the gills. The true amphi- 

 bious fishes respire by the latter method. No doubt we observe 

 that fishes which normally oxygenate their blood solely at their 

 crills, do rise to the surface in very hot weather, when the water is 



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