166 MR. F. J. COLE ON THE STEUCTUEE AND MORPHOLOGY OF 



which coursed backwards for an interval with the parent nerve, and then passed upwards, 

 crossed the lateral canal internally, and innervated a pit organ just dorsal to the canal. 

 By the time the parent nerve has reached the surface tubule 5 it has come to lie 

 immediately ventral to the lateral canal. Beyond this tubule the nerve gave off a dorsal 

 branch which pa«;sed upwards, pierced the second lateral line ossicle, and innervated 

 sense organ 6 of the line and its two closely associated pit organs. Posterior to the 

 origin of this twig a smaller one was given off which passed straight up and supplied a 

 pit organ dorsal to the body canal. Behind this again the branch arises which perforates 

 the third lateral line ossicle and is connected with sense-organ 7 of the line and its two 

 neiglil)0uring pit organs. 



The ventral or larger ramus of the lateralis trunk coursed backwards and steadily 

 downwards until reaching the pectoral fin, from which point it passed almost straight 

 backwards somewhat dorsal to the fin and following the line separating the dorsal from 

 the ventral musculatiu'e. I was unable, however, to detect any branches from its 

 anterior moiety. 



N. The Structure and Morphology of the Ramus lateralis accessorius. 



Synonymy. 



(1) Nervus lateralis accessorius (Weber, 1820). 



(2) Nerf pterigo-dorsal (Desmoulins & Magendie, 1825). 



(3) Ramus lateralis trigemini (Weber, 1827, and most other authors). 



(4) Ramus quartus s. lateralis nervi trigemini (Bonsdorff, 1846). 



(5) Dorsals Schedelholilenast (Stannius, 1849. Cp. also Hoffmann & Pollard). 



(6) Ramus recurrens trigemini et facialis (Stannius, 18i9). 



(7) Ramus recurrens facialis (Siluroids. Stannius, 1849. Cp. Pollard). 



(8) Ramus cutaneus quinti (T. J. Parker, 1884). 



(9) Nervus Weberi (Goronowitsch, 1897). 



(10) Nervus accessorius Weberi (iu part. Haller, 1897). 



Under the name of " ramus lateralis accessorius " (the reasons for retaining which are 

 given below) I propose to describe those curious and interesting nerves familiar to all 

 students who have dissected a Codfish, and which I at first thought were modified lateral 

 line nerves. A minute investigation of the roots, however, and, further, an examination 

 of the literature, convinced me not only that this conchision was absolutely erroneous, 

 but also pointed to the correct view, as I think, of theii- morphological value. This 

 small investigation also led to an examination of the essential meaning of the so-called 

 lateralis nerve of the Lamprey, the results of which, however, are given in the 

 succeeding section. 



That the so-called " cutaneus quinti " of Gadus corresponded to the " recurrent facial " 

 nerve described by Stannius and Pollard, was pointed out independently by Allis and 

 the writer — the former m his second Amia paper (6, p. 628), whilst a note to that effect 

 was inserted in the second English edition of Wiedersheim's "Comparative Anatomy" 

 (221, p. 187) at my suggestion. As, however, we were both anticipated by earlier 



