37 6 



has since designated (No. 7, p. 198) as a prophecy made by him 

 regarding the so-called dorsal branch of this nerve in Amia ; namely, 

 that it "would be found on investigation to be a branch of one of the 

 lateral line nerves". This is hardly an exact statement of the prophecy 

 referred to, which was (No. 5, p. 639) "that further investigation will 

 result in disassociating a portion of this nerve (where it innervates 

 a part of the lateral line system) from the IX th and placing it with 

 the other lateral line nerves". 



As to the latter part of this prophecy, as the branch was said by 

 me to arise, in larvae of Amia, by a separate root, to have a separate 

 ganglion of its own, and to innervate lateral sense organs and nothing 

 else, it could not well be otherwise placed than with the lateral line 

 nerves, and it seems to me that it was so placed by me by my 

 several statements that all the organs of the lateral system were 

 innervated by the so-called dorsal branches of the facialis , glosso- 

 pharyngeus and vagus. As to the first part of the prophecy — the 

 disassociation of the lateral branch from the IXth nerve — I can 

 not see how my statement, in jny later work , that the fibres of the 

 root of the nerve in Amia arise, all or in part , from the root of 

 the nervus lineae lateralis , should make it definitely a branch of 

 the latter nerve, and take definitely from it all possible segmental 

 association with the glossopharyngeus. Whether its association with 

 the glossopharyngeus is primary or secondary I do not pretend to 

 judge , but that the branch in Amia has the same relation to that 

 nerve, be it segmental or not , that the so-called facial and vagal 

 branches of the lateral system have to the facialis and vagus I con- 

 sider as unquestionable. And I may add that my work inclines me 

 to consider all these nerves as either primarily or secondarily seg- 

 mental , a conclusion wholly in accord with the following recent 

 statements by Johnston (No. 13, pp. 597 and 601) : "Obviously, if the 

 nerves of the V-VIII-lateral line group are alone homologous with 

 the dorsal roots of the spinal nerves, these alone can be compared 

 with those roots in determining segmentation" , and , "The sensory 

 V th , VIII th , and lateral line nerves alone are homologous with the 

 sensory roots of the spinal nerves." 



This finds further support in Alcock's work on Ammocoetes, which 

 I consider a valuable contribution to our knowledge of the lateral 

 sensory system, differing radically, in this, with Cole. The ventral 

 line of epidermal pits in Ammocoetes, for example, a part of which is 

 said to be innervated by a branch of the ventral branch of the glosso- 

 pharyngeus, explains, in all probability the gular line of pit organs in 

 Amia (No. 1, p. 519) a line of organs doubtless overlooked by Cole 

 in his statement (No. 7, p. 196) that: "The ventral line from the 

 IXth backwards is not represented in other recent or fossil Pishes." 

 Then the single organ innervated bj r what Alcock calls the third 

 branch of the facialis, seems to me to represent the entire supraorbital 

 line of Amia, and to confirm my opinion that that line is nothing more 

 nor less than a serial homologue of the middle head line of pit organs 

 of Amia, and of the other more posterior lines already referred to in 



