28 CORA J. BECKWITH. 



2. The auditory and lateral line organs of Amia do not have a 

 common anlage. The auditory organ arises before the lateral 

 line and independently of it as an invagination of the nervous 

 layer of the ectoderm and forms later a closed vesicle. 



3. The lateral line appears first in an embryo in which the 

 auditory organ is a closed vesicle. The four primary lines 

 (supra-orbital, infra-orbital, opercular-mandibular, and post-audi- 

 tory) all arise independently of one another and of the auditory 

 organ as thickenings of the nervous layer of the ectoderm and 

 unite later to form a continuous system. 



LITERATURE. 



Allis, Edward Phelps, Junior. 



'88 The Anatomy and Development of the Lateral Line System in Amia calva. 

 Journ. Morph., II., 463-458, Pis. XXX.-XLII. 

 Wilson, H. V. 



'91 The Embryology of the Sea Bass (Serranus atrarius). Bulletin U. S. Fish. 

 Com. Washington., IX. (1889), 209-277, Pis. LXXXVIII.-CVII. 

 Wilson, H. V., and Mattock, J. E. 



'97 The Lateral Sensory Anlage in the Salmon. Anatomischer Anzeiger, XIII., 

 658-660, two figures. 

 Mitrophanow, Paul. 



'93 Etude Embryogenique sur les Selachiens. Archives de Zool. Exp. (3), I. 

 160-220, PI. IX.-XIV. 



