Kingsbury, Brai7i of Ncctunis. 145 



band of fibers caudad of the mesencephal. Directly caud- 

 ad of this is the membranous roof of the metencephal, the 

 metatela, a portion of which is occupied by the metaplexus 

 which sends lateral projections cephalo-laterad on either side of 

 the mesencephal. 



Pigment is plentiful in the metaplexus and supraplexus ; 

 it also occurs upon the dorsal surface of the diencephal and 

 mesencephal and the lips of the metacoele caudad of the meta- 

 plexus. 



The meninges and blood supply of the brain have received 

 but incidental attention here. As regards the former, however, 

 as far as observed, the conditions in Ncctiirus appeared to agree 

 closely with those observed by Mrs. Gage ( '93 ) in 

 Dieniyctylus. 



The blood supply of the brain in AmpJiibia has been 

 worked out by Schobl ('82 ) and Rex ('92 ); by the former on a 

 number of urodeles of which Necturus is one. No attempt 

 has been here made to verify his accounts, save that, as found 

 by him, the capillary loops which penetrate the brain from the 

 vessels lying on the surface, although generally stopping at the 

 margin of the entocinerea, or penetrating it for a short distance 

 only, were also occasionally seen to reach the layer of endymal 

 cells. 



CRANIAL NERVES. 



No attempt has been made to study the peripheral dis- 

 tribution of the cranial nerves ; and, in fact, the apparent need 

 of it, existent at the time of Osborn's investigations, has been 

 largely obviated by the later publication of Strong, Von Plessen 

 and Herrick. The cranial nerves of Nechinis have also been 

 described and figured in some detail by Fischer ('64), although 

 some evident errors occur in his work. 



The description of the proximal relations of the several 

 nerves given here is based upon a series of sections through a 

 skull hardened in Hermann's fluid supplemented by macrosco- 

 pic dissections of decalcified specimens. 



I. The olfactory nerves are the largest of the cranial 

 nerves and arise from the ventro-lateral angle of the olfactory 



