The Lateral Sensory System in the Muraenidae. 165 



the eye, innervates a line of surface sense organs that lies directly 

 superficial to a section of the infraorbital canal extending from the 

 level of the centre of the eye forward to a point about halfway 

 between the eye and the anterior nasal aperture. The other portion 

 of the nerve runs downward and forward a short distance and then 

 turns backward and upward, and continuing- in this direction sends 

 branches backward or upward to each of the organs of the vertical line 

 of surface organs here under consideration. This latter line of organs 

 is thus quite certainly the homologue of the vertical cheek line of 

 pit-organs of Amia, and the line of organs below and in front of the 

 eye the homologue of the horizontal cheek line of pit-organs of Amia; 

 its position in Conger agreeing exactly with that of a similar line 

 in Esox (No. 9). The line of organs that lies parallel and nearly 

 superficial to the squamosal canal, then has no homologue in Amia, 

 but if it be a lateral sensory line innervated by a lateral sensory 

 branch the giossopharyngeus, it might represent that postotic squamosal 

 organ that has been shown to be lacking in the lateral canals of 

 Conger. As this innervation of the line is certainly possible, one 

 would then have the curious fact of a line of surface organs repre- 

 senting an organ that is usually found enclosed in a canal, while at 

 the same time the section of canal that should lodge this organ is 

 enclosed in a canal bone exactly as if the organ were there present. 

 While this would certainly complicate the question of the exact 

 relationship of the organ to the bone, it would just as certainly 

 further confirm some close relationship between them. It would even 

 then seem as if the vertical and horizontal cheek lines of pit-organs 

 must have, or must have had, some related bones; though what they 

 could have been is not apparent. 



Four other lines of surface organs remain to be described, three 

 on the head, and one on the lower jaw. They are all formed of 

 organs smaller than those just above described. One of the three 

 head lines is a short line that lies superficial to the dorsal portion 

 of the postorbital section of the main infraorbital canal. Its innervation 

 could not be traced. A second line runs downward between the eye 

 and the posterior nasal aperture, nearly to the level of the main 



