82 FISH GALLERY. 



Order IV. PHYSOSTOMI. 



[Case 17.] Bony fishes with all the fin-rays articulated, only the first of the 

 dorsal and pectoral fins sometimes ossified ; ventral fins, if present, 

 abdominal, without spine. Air-bladder, if present, with a pneu- 

 matic duct (except in Scombresocida) . 29 families : — 



1. Siluridce. 2. Characinidce. 3. Cyprinidce. 4. Haplochitonidce. 

 5. Sternoptychidce. 6. Scopelidce. 7. Stomiutidce. 8. Salmonidce. 

 9. Percopsidce. 10. Galaxidoe. 11. Mormyridce. 12. Esocidce. 

 13. Umbridce. 14. Scombresocida. 15. Cyprinodontidce. 16. 

 Heteropygii. 17. Gonorhjnchidce. 18. Hyodontidce. 19. Osteo- 

 glossidce. 20. Clupeidce. 21. Chirocentridce. 22. Bathythrissidce. 

 23. Alepocephalidcs. 24. Notopteridce. 25. Halosauridce. 26. iVo- 

 tacanthidce. 27. Gymnotida. 28. Symbranchidce. 29. Murcenidce. 



The Siluridce, or Cat-fishes (Cases 17, 18), are a large family, 

 represented by numerous genera, which exhibit a great variety of 

 form and structure of the fins. The skin is naked or protected by 

 osseous scutes, but without scales ; barbels are generally present. 

 These fish inhabit the fresh waters of all the temperate and 

 tropical regions ; a few only enter the sea, but keep near the coast. 

 The European species (Silurus glanis, fig. 68) is found in the 



Fijy. 68. 



/Ml 



Wels (Silurus glanis). 



waters east of the Ehine, and is, next to the Sturgeon, the largest 

 of European freshwater fishes, attaining to a weight of 300 or 

 400 lb. The " Bayad " (Bagrus bayad) is common in the Nile, 

 and grows to a length of over five feet ; it is eaten. Arius, of 



