Literary Notices. xxxvii 



to the brain, even in the region of the commissure; on the other hand 

 by the development in front of the proton of a general common rod 

 whose fibres pass into the brain considerably cephalad of the others. 

 At the same time the proton differentiates caudad into lateral nerve 

 and intestinal nerve (pneumo-gastric). 



6). The general cephalic root above mentioned is related 

 chiefly to the system of the lateral nerve. Springing from the brain 

 nearest to the facialis group, it descends behind the auditory vesicle 

 into the branchial region, contributing in its passage some fibres to the 

 glosso-pharyngeus and branchial rami of the vagus; these fibres serve 

 for the formation of the little suprabranchial rami which become at- 

 tached to parts of the branchial epidermal thickening ; they subse- 

 quently form the organs of the lateral line. The last of these supra- 

 branchial rami is especially developed to form the lateral nerve proper. 



For further theoretical discussion of these observations the author 

 refers to his work published in the transactions of the International 

 Zoological Congress at Moscow, 1892. 



(5). The spinal nerves are not discussed in this paper. 



II. Development of the Organs of the Lateral Line. 



After a detailed description of the mode and order of the devel- 

 opment of the mucus canals from the epidermis and of their innerva- 

 tion, the author presents the following summary : 



1 . At the beginning there is along the side of the head a general 

 auditory and branchial thickening. 



2. Its middle part, nearest the dorsal groove separates above the 

 hyoid arch to form the auditory lamella. [This is another link in the 

 chain of evidence which has been so rapidly strengthened of late, 

 showing the genetic relationship between the ear and the lateral line 

 organs.] 



3. While the latter is transforming into the auditory pit parts of 

 the hyoid and branchial arches separate from the branchial thicken- 

 ing, one after the other successively from before backwards. 



4. At the time of the transformation of the auditory pit into the 

 auditory vesicle, aside from the separation from the branchial thicken- 

 ing just mentioned, there is another from the anterior part, above the 

 first visceral cleft (spiraculum), and another from the lateral part be- 

 hind the auditory vesicle and above the branchial region. The sub- 

 sequent development of each of these parts is intimately associated 

 with that of the nerves with which they enter into close relations. 



5. The anterior part, separated from the thickening of the hyoid 



