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imens examined, with the double dendritic system formed where the terminal tube of the preoper- 

 cular canal anastomoses with the main infraorbital; a second, or third secondary connection thus 

 here being established between these two canals. 



Beyond the 8th. dendritic system the canal enters and traverses the postfrontal, at the hind 

 end of which bone it anastomoses with the penultimate tiibe of the supraorbital canal, a small double 

 System here arising from the canal. The canal then turns backward and traverses the pterotic, at 

 the hind end of which bone it anastomoses with the dorsal end of the preopercular canal, giving rise 

 to a double system, 10 inf.-12 pmd. This double system had, in the one satisfactory dissection 

 made, separated into two parts, one lying dorsal and the other ventral to the main infraorbital canal. 

 The dorsal one of these two portions was small, and opened on the outer surface in a small group 

 of pores, the ventral one being large and undergoing anastomosis not only with the 8 th. infraorbital 

 System, as above described, but also with the 11 th. system of that same line. This last anastomosis 

 gives rise to a large and complicated system which spreads backward in the dermis that Covers the 

 levator operculi muscle, extending even beyond that muscle onto the dorsal portion of the outer 

 surface of the opercular. 



Posterior to the 10 th. tube of the line, the main infraorbital canal traverses the lateral extra- 

 scapular and then the suprascapular and supraclavicular, the 1 1 th. tube of the line being given off 

 between the first two bones, the 12 th. tube between the last two, and the 13 th. tube at the hind 

 end of the supraclavicular. The 11 th. tube gives rise, as just above stated, to a large dendritic system 

 which anastomoses with the ventral half of the double system 10 inf.-12 pmd. The 12 th. and 

 13 th. Systems are small. 



In the füll length of the main infraorbital canal there are twelve sense organs, one organ thus 

 being found between each two consecutive primary tubes. Three of these organs lie in the lachrymal, 

 one in the first suborbital, two in the second suborbital, one in the postorbital ossicle, and one each 

 in the postfrontal, pterotic, lateral extrascapular, suprascapular and supraclavicular. The first six 

 organs of the line are each innervated by consecutive and independent branches of the ramus buccalis 

 facialis. The eighth (postfrontal) and ninth (pterotic) organs are innervated by branches of the ramus 

 oticus facialis. The Innervation of the 7th., or postorbital organ could not be determined either 

 in the sections or the dissections, but it is quite unquestionably innervated by a nerve that corres- 

 ponds to that somewhat independant brauch of the buccalis that innervates, in Amia, the posterior 

 group of buccal organs of that fish. If this be so, the postorbital break in the main infraorbital canal 

 occurs between two groups of organs of the line, and is strictly similar to the break found in, this 

 same line in Batrachus tau (Clapp, '98) and Chimaera monstrosa (Cole, '96), and to which I have 

 made füll reference in several of my works. 



The 10 th. (extrascapular) and llth. (suprascapular) organs are innervated by branches of 

 the supratemporal brauch of the nervus lineae lateralis vagi; the 12 th. (supraclavicular) organ being 

 innervated by the first single brauch of the latter nerve. 



The supratemporal canal arises from the main infraorbital canal as that canal traverses the 

 lateral extrascapular. Eunning mesially it traverses the lateral extrascapular and then the parieto- 

 extrascapular, and then unites, in the mid-dorsal line, with its fellow of the opposite side, thus 

 forming a complete cross-commissure. As the canal passes from the lateral extrascapular into the 

 parieto-extrascapular it gives off a primary tube which separates into two parts one directed anteriorly 

 and the other posteriorly and both giving rise to relatively important dendritic Systems. A similar 



