198 HYPOTHALMUS. 



Before taking leave of this family, we must notice 

 a structure of a very beautiful description which 

 characterises the articulation of the dorsal fin, and 

 seems to be present, so far as we can judge from 

 outward appearance, in most of the families of the 

 Siluridge. The subject of the annexed engraving. 



PLATE X. 



Was picked up on the sea- shore at Bombay, and 

 was brought to us by James Inglis, Esq. M. D., who 

 was much struck with the singular structure, for the 

 purpose of ascertaining to what animal it belonged : 

 being occupied at the time in examining some spe- 

 cimens of this family, we immediately set it down 

 as the first dorsal spine of one of the Siluri of India, 

 and our opinion was very soon confirmed by the 

 dissection of a small specimen of one of the Siluri 

 or Pimelodi from North America, which was kindly 

 given to us by Dr. Parnell for that purpose, and 

 where we discovered the very same ringed articula- 

 tion. It will be for future observers to attend par- 

 ticularly to the uses to which this spine is applied 

 to require so complicated an arrangement. Is it 

 ever struck into its enemies or prey, in attack or 

 defence ; and will the ring preserve it from dislo- 

 cation in the extraction, which would be rendered 

 difficult from the barbed spines ? 



