24 H. B. POLLARD. 



appears to be Facial, and finally in " Ganoids," elements of the Glosso- 

 phaiyngens enter into its composition (v. AVijhe). 



Therefore, in considei'ing its homologies, various components must 

 be recognised in the palatine, and I consider the most anterior branches 

 a dissociated portion of the R. premaxillaris. The most anterior 

 tentacle of Cyprinoids is supplied by a nerve, of which Biichner has 

 given a most excellent description (in Barbus). He terms it maxillaris 

 superior. " It springs from the anterior internal boi'der of the ganglion, 

 passes in a canal formed by the upper convex face of the body of the 

 sphenoid (parasphenoid) and the base of the greater (prootic) and lesser 

 wing (orbitosphenoid) and is directed along the internal wall of the 

 orbit, passes between the anterior frontal (ectethmoid) and palatine 

 along the vomer and forms a kind of plexus with a branch of the 

 maxillaris inferior (R. nix. superior), From this plexus start three 

 branches for the two barbels and for the fleshy lip along the inter- 

 maxillary. That of the superior barbel passes through a foramen, 

 hollowed out at the internal extremity of the maxillary bone." 



Sagemehl has described the nerve as palatine in Cyprinoids and 

 agrees with Biichner, and I have myself fullowed the course of the 

 nerve by sections and dissections in Misgurnus fossilis. It takes a 

 course intermediate between those of the R. premaxillaris and R. 

 palatinus of Siluroids, inasmuch as it passes below the prepalatine 

 piece. I take it therefore, that this nerve almost universally termed 

 palatine contains palatine and premaxillary fibres and corresponds to 

 the Premaxillaris of Myxlne. 



The R. palatinus has been described in detail in the Sturgeon by 

 Stannius and v. Wijhe, "In Acipenser the N. palatinus has relations 

 really corresponding to those of Teleostei" (Stannius). "It runs forward 

 along the lateral edge of the parasphenoid, separated from the 

 orbit by a paired outgrowth of cartilage from the basis crauii. In front 

 of this the nerve forms a network with the Ramus maxillaris superior, 

 and then sends branches to the snout and ends in the tentacles '' (v. 

 Wijhe). 



The barbels of Sturgeons are therefore premaxillary and maxillary 

 tentacles. 



Maxillary and coronoid Tentacles. 

 Maxillary tentacles are shown most typically in Triclwmycterus and 



