The Lateral Sensory System of the Muraenidae. 129 



and then entirely in the latter bone. In this canal the main infra- 

 orhital canal runs backward neaii}^ to the hind end of the skull, where 

 it issues on the dorsal surface of the squamosal that bone extending 

 to. and forming- part of, the hind edg-e of the skull. In this long 

 s(iuamosal section of the main infraorbital canal there was, so far as 

 could be determined, but a single sense organ. 



Having left the canal in the squamosal the - main infraorbital 

 canal enters and traverses a short cylindrical ossicle, and then opens 

 into the anterior wall of a transverse sensory canal formed by the 

 end-to-end anastomosis of the supratemporal commissure and the pre- 

 operculo-mandibular canal. From the opposite wall of this same trans- 

 verse canal the lateral canal of the body begins. In the short 

 section of sensory canal enclosed in the short cylindrical ossicle there 

 is no sense organ, and no primary tube arises from the main infi-a- 

 orbital canal posterior to the one that issues between the postfrontal 

 and upper postorbital bones. 



The supraorbital canal has every appearance of beginning at a 

 pore that lies on the antero-ventral surface of the anterior end of 

 the snout. From there it runs backward and upward, enters a cen- 

 tral cavity in this part of the skull, and issues from it about midway 

 between the above mentioned pore and the anterior nasal aperture. 

 There a primary tube is given off which opens on the outer surface 

 by a single pore, the canal itself continuing backward and immediately 

 entering the anterior end of the nasal bone. The section of sensory 

 canal enclosed between the two pores above described is, in appearance, 

 as above stated, a part of the supraorbital canal, but comparison with 

 Conger leaves no doubt that the organ or organs it contains are 

 innervated by the buccalis facialis and not by the ophthalmicus super- 

 ficialis, and that it is accordingly an ethmoidal canal and not a section 

 of the supraorbital one. The pore at the hind end of this section of 

 canal is thus a double pore formed where the ethmoid and supraorbital 

 canals anastomose. 



Starting from this pore the supraorbital canal runs almost 

 directly backward to a point dorso-mesial to the hind edge of the eye, 

 where it turns latero-ventro-posteriorly and anastomoses with the 



9 

 Internationale Monatsschrift für Anat. u. Phys. XX. 



