THE NERVUS TERMINALIS IN THE CARP. 



R. E. SHELDON. 

 From the Anatoinkal Luburutury of the University of Chicago. 



With Seven Figures. 



Fritsch figured in 1878 the stump of a nerve arising mesad of the 

 olfactory from the rostral aspect of the brain of Galeus canis. This 

 he called an "iiberzahliger Nerv." Our present knowledge concern- 

 ing it is, however, due almost entirely to the work of the last few 

 vears, during which its existence has been demonstrated in group 

 after group among the lower vertebrates. Pinkus, '94, '95, in Pro- 

 topterus was the first to trace and describe the entire course of the 

 nerve which he called simply, ''ein neuer ISTerv." Allis, '97, found 

 the nerve in Amia but added nothing concerning its structure and 

 connections, naming it, however, the nerve of Pinkus. Tocy, '99, 

 in Acanthias described a nerve, closely associated with the olfac- 

 tory, as in the cases previously reported, but ganglionated. Pinkiis 

 had founds cells in connection with the nerve in Protopterus, but 

 hesitated to call them a ganglion. In 1902 Sewertzoff described 

 in Ceratodus embryos a similar ganglionic nerve which he named 

 the nervus preopticus owing to the fact that it appears to arise near 

 the preoptic recess in Dipnoans. Later, Burckhardt, in 1905, found 

 the same nerve in adult Ceratodus. Locy in several papers, '03, 

 '05a, '05b, takes up in detail its occurrence in different groups of sela- 

 chians, its peripheral and central connections and its embryonic 

 history. He pointed out its homology with the nerve of Pinkus in 

 Protopterus and Amia and the nervus preopticus of Ceratodus, pro- 

 posing for it the name of nervus terminalis. Brookover, '08, demon- 

 strated a ganglion for the nerve in Amia and Lepidosteus, adding 

 also to our knowledge of its peripheral connections. 



The Jouenal of Co.mi'Arative Nelt.ology and Psychology. — Vol. XIX, No. 2. 



