206 On Isinglass in Polynemus sele, Buck. [March, 



be really common to the eastward ; if so, it seems strange that the Chinese 

 should send for it to the Hoogly. Next, do the Pol. Emoi and Pol. 

 plebeius, supposed by Buchanan to correspond with his Sele, contain the 

 same valuable substance ? and do either of Russell's species, namely, the 

 Maga booshee and Magajellee, (Indian Fishes, 183, 184,) yield it ? These 

 are questions easily determined along our coasts by merely opening such 

 fish as correspond with the one here figured, and ascertaining whether 

 they contain an air vessel or not, and whether that vessel if present be 

 large or small. Mergui, Batavia, Singapore, Tranquebar, Madras, and 

 Bombay are points a-t which observations might be made. This question 

 may be so easily ascertained, that it is hardly worth forming a conjecture 

 about it ; but if any of the species common to the coasts of the Eastern 

 seas possessed so valuable a property, the chances are that it would 

 have been long since discovered. It is therefore probable that the 

 large gelatine sound will be found to be peculiar to Pol. sele, and per- 

 haps Pol. teria* Buch. both of which seem to resort chiefly to the 

 Gangetic estuaries at certain seasons, particularly during the North- 

 east monsoon, when it is easy to imagine that the shelter afforded in 

 those estuaries at that season, might account for many peculiarities 

 which their ichthyology appears to present, compared with that of open] 

 coasts. It is during the cold season that the two gigantic fishes above! 

 mentioned appear to be caught in most abundance, a circumstance the; 

 more favourable to any improved operations that might be resorted 

 to with a view to convert them to useful purposes. Whether both con-' 

 tain- the same valuable substance, I am unable to say, having as yet 

 only examined P. sele. 



Gen.— POLYNEMUS. 

 Two fins on the back, with long filaments attached to the sides in front 

 of the pectoral fins. Opercula covered with scales ; preoperculum 

 serrated behind. Example. The common Mango-fish of Bengal. 

 Yielding Isinglass. 

 P. Sele, Buch. Plate — 

 Sele, or Sulea of the Bengalese. 

 Five filaments, the first reaching from the front of the pectorals to 

 midway between those fins and the anal,, the other filaments progres- 

 sively shorter ; no streaks on the sides, lateral line deflected on the lower 

 lobe of the caudal fin. The fin rays are as follows ; — first dorsal seven, 

 second dorsal fourteen, pectorals thirteen in each, ventrals each six, 

 anal twelve or thirteen, caudal twenty (?) The teeth are very fine, con- 

 tinuous below round the edes of the jaws, but interrupted at the 



P. 2Mdrifilis t t'uY. P. iQiradQCiylus, &c. and probably refer to the same 



