Order I. PHYSOSTOMI, Muller. 



All the fin-rays articulated with the exception of the first in 

 the dorsal and pectoral, which are frequently more or less ossified. 

 Ventral fins, when present, abdominal and spineless. Air-vessel, 

 if existing, having a pneumatic duct (except in the family Scom- 

 bresoddce). 



This order contains the largest proportion of the freshwater 

 fishes of India. The family Siluridce or sheat-fishes are destitute 

 of scales ; the carps, Cyprinidce, have scaled bodies but no teeth in 

 the jaws ; while the herrings, Clupeidce, are likewise scaled, and 

 have some teeth in the jaws and a carinate abdominal edge. 



Synopsis of Indian Families. 



I. Fishes with eel-like bodies. Margin of upper jaw 



formed of the premaxillaries, the maxillaries 

 being internal and parallel to them. Vertical 

 fins rudimentary, and no paired fins. Gill-open- 

 ings in the form of a single slit. Scales, if present, 

 minute. Accessory breathing-organs may be pre- 

 sent. No air-bladder. Stomach without a blind 

 sac ; no pyloric caeca. Ovaries with oviducts. Symbranchidae. 



II. Fishes with eel-like bodies. Margin of upper 



law formed anteriorly by the premaxillaries and 

 laterally by the maxillaries. Pectoral fins 

 present or absent; no ventrals. No accessory 

 breathing-organs. Stomach with a blind sac; 

 no pyloric caeca. Ovaries without oviducts . . Muraenidae. 



III. Subopercle absent. Margin of upper jaw 

 formed by the premaxillaries. Skin scaleless and 

 smooth, or covered with osseous plates or scat- 

 tered tubercles. Adipose dorsal usually present. Siluridae. 



IV. Pseudobranchiae, when present, glandular. Mar- 

 gin of the upper jaw formed by the pre- 

 maxillaries. Opercular pieces complete. Mouth 

 toothless, teeth in lower pharyngeals. Head 

 scaleless ; body scaled or scaleless, never covered 



by osseous plates. Air-bladder present or absent. Cyprinidae. 



V. Pseudobranchiae absent. Margin of upper jaw 



formed by the premaxillaries and maxillaries, 

 which are toothed. Opercular pieces complete. 

 No barbels. Dorsal fin in caudal portion of body. 

 Stomach with blind sac; intestinal canal short, 

 and furnished with spiral folds. No pyloric caeca. 

 An air-bladder Chirocentridae. 



VI. Pseudobranchiae usually well developed. Mar- 

 gin of the upper jaw formed by premaxillaries 

 and maxillaries. Opercular pieces complete. 



