MDSTELUS L/EVIS. 99 



temporal cross-commissure — a point that could not be defi- 

 nitely determined, tlie sections there being slightly broken. 



From the hind end of the median section of the canal to the 

 point where the canal joins the anterior end of the supra- 

 orbital canal there are 16 sense organs, the two canals 

 anastomosing immediately beyond organ 45 infra-orbital. 

 The organs along the entire line up to this point, that is, 

 organs 1 to 45, are all innervated by branches of a single 

 large branch of the buccalis facialis, but organs 1 to 25 

 form a sub-group somewhat separate, in their manner of 

 innervation, from organs 26 to 45. 



Posterior to the point where the canal anastomoses with 

 the distal end of the supra-orbital canal, and back to the point 

 where the hyomandibular canal is given off, there are nine 

 sense organs, 46 to 54, and their innervation by two separate 

 branches of the buccalis indicates that they form a separate 

 sub-group, or two such groups, of infra- orbital organs. This 

 section of canal and the one that contains organs 30 to 45, 

 together form the nasal canal of Garman's descriptions, that 

 section of canal thus not being a morphological unit. Organs 

 55 to 69 lie in the two arms of the suborbital bend of the canal, 

 that is, in that part of the canal that lies between the point 

 where the hyomandibular canal is given off, and a point near 

 the anterior end of the ventral edge of the eye. This section 

 of canal thus includes the orbito-nasal of Garman and a part 

 of his sub-orbital, not corresponding exactly to any of his 

 sections. These organs, in their innervation, form a distinct 

 sub-gi*oup of the infra-orbital line, as do also organs 70 to 

 74, organs 75 to 78, organs 79 to 82, and organs 83 to 8(j, all 

 of which lie in the sub-orbital part of the canal. These 41 

 organs together, that is, organs 46 to 86 inclusive, form what 

 may be called a large sub-orbital group, in which there are 

 six well-marked sub-groups. 



Posterior to organ 86 the remaining organs of the line, back 

 to the point where the supratemporal cross-commissure is 

 given off, are all innervated by three branches that arise 

 close together from a posterior prolongation of the gangHon 



