626 



MR, R, H. BURNE ON THE ANATOMY OF THE [May 25, 



maxillary tentacle are similar to those observed in Clarias, and 

 there is little doubt that in a similar way it follows the move- 

 ments of the palatine bar and acts as an aspirator bulb, though 

 probably in a feeble way, to produce water currents through the 

 leaves of the olfactory i-osette. 



N.S. 



Text-fig. 197. 



M.ETH. /1/.5. 



MX.T. 



Malapterums electricus. 

 The olfactorj' organs shown as in text-fig. 196. 

 MX.T., maxillary tentacle. 



Pimeloclus sebce. 



The nostrils are very similar to those of Clarias though the 

 posterior is smaller, not so distinctly A^alved, and not connected 

 with a tentacle. 



The olfactory chamber is a narrow oval cavity stretching from 

 nostril to nostril and is completely occupied by a long oval rosette 

 fastened to its floor. Its outer wall lies parallel to, but not in any 

 connection with, the palatine bar, and although the movements of 

 the tentacle are effected by a mechanism similar to that in Clarias 

 and MaUqyterurus, there can be little or no movement com- 

 municated to the walls of the olfactory chamber. 



Silurus glanis. 



The nostrils are essentially similar to those of the other 

 Siluroids examined. The anterior lies at the end of a short tube 

 the hinder margin of which is produced as in Makq^terurus to 

 form a short tentacular process. The posterior lies some consider- 

 able distance (at least twice the diameter of the eye) fui-ther back 

 and is a longitudinal slit bordered by valvular folds. 



The nasal cavity occupies the space between the nostrils and is 

 separable into an anterior half, lodging the rosette, and a vacant 

 posterior half. 



