THE RAMUS LATERALIS ACCESSORIUS. 24I 



of our Standard text-books {e. g., Minot's and Hertwig- 

 Mark's Embryologies), it seems desirable to emphasize 

 the matter again. 



Section 12. — General Considerations. 

 I. — The Ramus Lateralis Accessorius. 



This nerve is the r. recurrens facialis, the r. lateralis 

 trigemini and the superficial lateral line nerve of the 

 literature. It and related nerves have also received many- 

 other names. By previous writers it has very generally 

 been regarded as morphologically analogous with the r. 

 lateralis vagi. It is, however, now known that this is not 

 the case and the term lateralis accessorius has hitherto 

 been avoided by me as suggesting bad morphology. The 

 reasons, however, given by Cole ('98a) for the retention of 

 this good old term of Weber's seem to me to be sufficient ; 

 it is merely necessary to keep constantly in mind that 

 this nerve has no morphological relationship whatever 

 with the r. lateralis vagi. 



This nerve arises by two root complexes, one from the 

 vagus system, the other from the facial. These anasto- 

 mose above and behind the cranium and the combined 

 nerve runs back into the trunk near the dorso-median 

 line. The most interesting morphological question in 

 this connection is the problem of the relation of this nerve 

 and the organs of the accessory lateral lines supplied by it 

 to the r. lateralis vagi and the main lateral line. As I have 

 before remarked, all of the cutaneous sense organs are 

 somewhat reduced in Menidia and especially the terminal 

 buds, so that this is not a favorable type for the solution 

 of this problem. In effecting the analysis of these nerves 

 we must rely mainly upon the calibre of the nerve fibres 

 and the problem is complicated greatly in this species by 



