Reprinted from the " Zoologische Jahrbucher Bd. VIII., Abth., 



F. MORPH." 



THE ORAL CIRRI OF SILUROIDS AND THE ORIGIN OF 

 THE HEAD IN VERTEBRATES. 



By Dr. H. B. Pollard, Berkeley Felloiv in the Owe?is College, Manchester. 



With Plates I— II. 



Contents. 



Introduction. 



Technique. 



On the occurrence of oral cirri. 



Descriptive part : 



Models of Auchenaspis, Sihiras, Trichomycterus and Callichthys. 



Sensory tentacular nerves of Auchenaspis, Trichomycterus, Callichthys 

 and Myxine. . 

 Comparative part : 



Nasal tentacle and nerve supply. 



Premaxillary tentacle and nerve supply. 



Maxillary and coronoid tentacles. 



Origin of the cranium. 



Labials and nerve supply. 



Mental tentacle and extramental. 



Submandibular tentacle. 



The Meckel ian cartilage. 



Other parts of the head. 

 Histology. 



Reversion and larval forms. 

 Zoological position of Siluroids. 



Introduction. 



Nearly four years ago, I found in the cellar of the Anatomical 

 Buildings at Freiburg i./B. a number of Siluroids, which Professor 

 Wiedersheim openhandedly placed at my disposal, and I then began 



