634 A. A. W. HUBREOHT. 



early stage eminently lateral, a conclusion corroborated by 

 the figures of his actual sections. This primitive position is, 

 of course, gradually lost, and could never be predicted from 

 a study of these ganglia and their position and significance in 

 the adult animal. Yet it is not without significance when seen 

 in the light of the suggestion here brought forward. And that 

 the interpretation of the phenomena in question as given by 

 these authors is not universally accepted, thus leaving room 

 for new suggestions, is proved by the following citation from 

 Hansom's and d'Arcy Thompson's latest article,^ running as 

 follows: — ''Although the lamprey presents a well-marked 

 lateralis nerve it has not also a regular lateral line, for the 

 sense-organs of the skin are scattered and without segmental 

 arrangement. The sense-organs do not, therefore, appear to 

 be in direct relation with the spinal ganglia, and the view of 

 the close connection between them (Spencer, Beard, Froriep) 



does not receive support It seems more natural to 



consider the lateralis as a relic of the extensive and irregu- 

 lar commissure system connecting the posterior roots of 

 Amphioxus." 



Passing from a consideration of the embryonic ganglia to 

 their connection in the adults, I must mention the connection 

 of the ramus lateralis vagi with cephalic nerves anterior to 

 the vagus. I will not here give a description of the numerous 

 varieties presented by this nervous connection, but merely 

 refer to the arrangement in Vertebrates so low as the lam- 

 preys. We there find, according to Johannes Miiller, the 

 ramus lateralis originating from the seventh as well as from 

 the tenth pair of cephalic nerves, and if we compare the very 

 satisfactory figure which was only lately^ given by Ahlborn 

 of this arrangement, we must recognise that this nervous con- 

 nection is important, and has more the aspect of a direct for- 

 ward continuation of the nervus lateralis than of a sensory 



1 " On the Spinal and Visceral Nerves of Cyclostomata," ' Zoo). Anzeiger,' 

 No. 227, July, 1886. 



' ' Zeitschr. f. wiss. Zool.,' Bd. xl, pi. xviii. 



