2 24 CLAP P. [Vol. XV. 



In the following pages an attempt has been made to describe 

 the lateral line system of the toadfish, both in the adult and 

 developmental stages, for, as Mr. Allis (2) has well said, the 

 "purely descriptive part of the subject" has been too much 

 neglected. 



Frequent reference will be made to the conditions existing 

 in Amia, and the nomenclature employed by Allis will be 

 adopted. 



Ryder (3) describes the appearance of the lateral line organs 

 in the young toadfish at the time of the formation of canals on 

 the head, and speaks of the lines of free organs on the body 

 as canals ! It is evident that his observations, though in many 

 ways valuable, were incomplete. So far as I am aware, this 

 preliminary "notice" contains all we have on the subject of 

 the lateral line system of the toadfish. 



In Jordan's "Synopsis of Fishes of North America" (4) the 

 only mention of this system is the statement that in B2,trachus 

 there is " no lateral line, nor conspicuous pores." 



My study of the lateral line system of Batrachus was begun 

 in the summer of 1888, under the direction of Prof. C. O. 

 Whitman, at the Marine Biological Laboratory of Woods Holl, 

 Mass., and completed at the University of Chicago. 



I wish to express my deep feeling of obligation to Pro- 

 fessor Whitman for the interest he has taken in the supervi- 

 sion of my work ; and for the many courtesies and suggestions 

 received from instructors and associates, I wish here to make 

 acknowledgment. 



For assistance in obtaining material at Woods Holl I am 

 greatly indebted to Mr. G. M. Gray, the Collector of the 

 Marine Biological Laboratory ; for specimens of Acanthias I 

 wish to thank Dr. A. D. Mead and Prof. A. D. Morrill. 



The drawings for this paper were made after my sketches 

 by the following draughtsmen at the Marine Biological 

 Laboratory : 



