408 H. B. POLLARD, 



Nerre Supply. 



It is impossible in Siluroids to sharply define maxillary and coro- 

 noid nerves inasmuch as many fibres runninfî along with the maxil- 

 laris supply the coronoid tentacle. However there is always a coronoid 

 branch arising from the mandibularis and supplying the posterior face 

 of the coronoid tentacle. Where the coronoid and maxillary tentacles 

 are fused, as in Auchenaspis , the branch is still jiresent in exactly 

 the same relation, and this indeed is one of the proofs that the 

 maxillo-coronoid tentacle contains maxillary and coronoid elements. 

 A similar coronoid branch is described as arising from the mandibular 

 nerve in larval Salamanders, by von Plessen & Rabinowicz. 



As to Myxine, the second branch of the Trigeminus divides into 

 maxillary and coronoid branches, apart from motor nerves. They 

 supply maxillary and coronoid tentacles and the skin between them. 



Stannius gives further descriptions of the distribution of the 

 maxillaris superior in Silurus and Acipenser, mentioning the i)re- 

 maxillary branch in Silurus. He states that the maxillaris superior 

 supplies the upper labial cartilages in Spinax. 



Büchner figures the maxillaris superior in Barhus as an upper 

 branch of the maxillaris inferior. He describes its course and its 

 anastomosis with the premaxillary nerve (his maxillaris superior). The 

 literature of the cranial nerves is immense but I do not think the 

 facts need further reviewing here. 



Mental Tentacle. 



The mental tentacles of CalUchthys are fused at their bases, the 

 fused i)ortion lying medially in front of the symphysis of the deutary 

 bones. Thence the tentacle curves down on each side and, never 

 really becoming free to the exterior, fuses distally with the proximal 

 part of the coronoid tentacle. There is no special root piece. In 

 Silurus the mental tentacle is situated some little way back from the 

 symphysis along the lower jaw, being supported by a plate of pro- 

 cartilage lying just internal to the skin. To this are attached muscles. 

 The condition in Anchenaspis is similar, the basal plate being however 

 very much larger. In Auchenaspis there is situated at the outside 

 of the dentary bone a large block of i)rocartilage (Ment. p.) with a 

 posterior ventral jirojection running parallel with the tentacle as shown 

 in Fig. 2. This block may be a derivative of the tentacle , possibly 

 arising as a bifurcation of the proximal portion. Such a bifurcation 



