166 Edward Phelps AUis jr., The Lateral Sensory System in the Muraenidae. 



infraorbital canal where it turns forward and is continued a considerable 

 distance. A third line lies dorso-mesial to the posterior nasal aperture, 

 and is continued forward to the end of the snout by an irregular line, 

 or scattered g'roup, of much smaller organs. The organs of the second 

 line, and the larger organs of the third line, are all innervated by a 

 branch of a nerve that accompanies the ramus ophthalmicus super- 

 ficialis, and that could be traced backward with that nerve, but as a 

 separate strand, to the foramen by which it issued from the skull. 

 The second line forms, together with the postorbital part of the main 

 infraorbital canal, the vertical cheek line of pit- organs, the preoper- 

 cular canal line, and the S-shaped line on the gill-cover, five des- 

 cending sensory lines of the side of the head of the fish. 



The line of surface organs on the lower jaw lies slightly mesial 

 to, and parallel to, the anterior end of the mandibular sensory canal. 

 It is innervated by a nerve that is associated with, if not a branch 

 of, a large nerve that is distributed to the dermal tissues of the dorso- 

 lateral part of the mandible. The united nerves turn upward at the 

 hind end of the mandible, there passing external to all the ligaments 

 that connect the mandible with the opercular bones, the suspensorial 

 apparatus, and the ceratohyal. Passing internal to the adductor 

 mandibulae muscle, the nerves run upward along the outer surface of 

 the fused quadrate and hyomandibular and enter a foramen between 

 the adjoining edges of those two bones, there joining the truncus 

 hyoideo-mandibularis facialis. The mandibular line of surface organs 

 would thus seem, from its innervation, to correspond to the mandibular 

 line of pit-organs of Amia. 



Palais Carnolès, Menton. May 18*^ 1902. 



