6 SYDNEY EVANS JOHNSON 



Morrill's demonstration ('98) of the nature of nerve termina- 

 tions among the hair-cells of the ampullae of the ear is equally 

 distmct on the side of contiguity. This paper wdth its excel- 

 lent results has been frequently overlooked even by inve.stigators 

 of the nerve terminations of the eighth nerve. 



Neurological investigations led finally to the recognition that 

 we have free nerve terminations among sensory cells and these 

 came to be designated as secondary sense cells. In the sensory 

 epithelium of the lateral canals we have a good illu.stration of 

 these secondary sense cells. 



The literature in reference to topography and gross distri- 

 bution of the nerves is extensive and embraces widely known 

 standard contributions as those of Malbranch '76, Amphibians; 

 Ramsay Wright '84, Ameiurus; Garman '88, Selachians; Allis 

 '88, Amia, and others. Following these are the papers of Ewart 

 '93, Lemargus; Ewart and Mitchell '93, Raia; Cole '95, Chi- 

 maera; Colhnge '94, Fishes; Clapp '98, Batrachus; Allis '02, 

 Mustelus; Norris '07, Amphibians; Ayers and Worthington '07, 

 Edellostoma; Reese '10, Chimaera. 



In reference to the acustico-lateraUs system of nerves con- 

 tributions have been made by Herrick '99, '01, '05, '06; Johns- 

 ton '06; Landacre '14, ganglia, etc. A number of authors have 

 particularly emphasized the relationship between the ^sensory 

 canal system and the ear. 



On the embryological side Balfour's classic observations on 

 elasmobranch fishes ('78) mark the beginning. Other embryo- 

 logical studies include those of Beard '83, metameric condi- 

 tion; Allis '88, connection between ear and nose; Mitrophanow 

 '93, surface views of development from a primordium embracing 

 the epitheliimi of the ear; Wilson and Mattocks '95, primordia 

 of ear, lateral line and branchial gangha forming a fm-row and 

 sac; Harrison '03, experimental observations of the growth of 

 lateral line organs of amphibia. 



The publications that are more closely related to the subject 

 of this paper are those showing histology of the sense organs 

 and their nerve terminations excluding those that relate spe- 

 cifically to the ampullae of Lorenzini and the vesicles of Savi. 



