140 Edward Phelps Allis jr., 



Main infraorbital canal. 



The main infraorbital sensory canal of the adult Cong-er begins 

 anteriorly at a pore that lies slightly dorso-mesial to the base of 

 the nasal tube of the fish. This pore is prolonged to form a slight 

 tube which is directed dorsally and mesially, directly toward a similar 

 but much larger tube that is developed in relation to pore No. 1 

 of the supraorbital canal. These two short tubes are separated by a 

 small pit, and the tubes are pressed and flattened down into the pit 

 so that they may be said to open into it, directly opposite to, and 

 quite close to, each other. The pore at the outer end of each tube 

 is thus also flattened, and they appear, in both alcoholic and fresh 

 specimens, as long, oval, or slit-like openings, the long axis of the 

 oval lying practically in the direction of the course of the main canal 

 to which the pore belongs. This oval or slit-like form is character- 

 istic of all the pores on the head of Conger, the more posterior 

 pores being simply relatively long slits, the edges of which are formed 

 by delicate membranous lips which touch each other and almost close 

 the opening of the pore. These latter pores have, in fact, much the 

 appearance of the primary pores of larvae of Amia just before they 

 undergo their first dichotomous division. The mid-dorsal pore of the 

 supratemporal commissure and the pores of the lateral canal of the 

 body, are small and round, in marked distinction to the pores on 

 the head. 



Starting at pore No. 1 , the main infraorbital canal runs back- 

 ward under the eye in a nearly straight line, and then turns sharply 

 upward, and upward and forward behind the eye. Dorso-mesial to 

 the eye, the canal lies on the flat dorsal surface of the head, there 

 running postero-mesially and meeting and anastomosing with the supra- 

 orbital canal; but with which one of the primary tubes of this latter 

 canal the anastomosis is made it is impossible to definitely tell, though 

 it is alsmost certainly with the terminal tube. After this anastomosis 

 the canal turns sharply backward and laterally, and continues in a 

 pearly straight line to the hind edge of the skull. There it turns 

 sharply still more laterally, and after a short course opens directly 

 into the continuous transverse canal here formed by the union, at 



