36 Journal of Comparative Neurology. 



Fig. lo. Amiurus. Transection farther cephalad, the fasciculus communis 

 is dorsal {/. v.), the spinal Vth and the almost entirely reduced dorsal cornua 

 are displaced. 



Fig. II. Amiurus. Transection at the level of the exit of the Vllth roots. 

 Intermediate between this and figure lo is figure 24 at the entrance of the IX?, 

 showing the developing acusticums. 



Fig. 12, Perca. Transection of the oblongata at the exit of the Xth nerve. 

 A component from the spinal Vth tract is shown. 



Fig. ij. Amia. Transection through the myel showing the enlarged dor- 

 sal cornua. (Comp. fig. 6 and figs. 15-18.) 



Fig. 14. Notemigonus. Transection through the oblongata at the exit of 

 the Xth nerve. 



PLATE III. 



Fig. ij. Amia. Transection of the oblongata at the first (recognizable) 

 appearance of the fasciculus communis system. 



Fig. 16. Amia. Transection farther cephalad near the caudal appearance 

 of the acusticum and the cerebellar crest. 



Fig. ly. Amia. Transection at the level of the IXth. 



Fig. iS. Amia. Transection of the oblongata at the exit of the VII- 

 Vlllth nerves. 



Fig. ig. Perca. Transection of the oblongata caudad of the Vlllth 

 showing the fusion of the acusticums. 



Fig. 20. Esox. Transection of the oblongata at the exit of the Vlllth. 



PLATE IV. 



Fig. 21. Catostomus. Transection of the brain at the exit of the Xth. A 

 fusion of the vagal lobes is shown. (Comp. figure 14 of the corresponding 

 level in Notemigonus.) 



Fig. 22. Catostomus. Transection farther cephalad including the tuber- 

 culum impar, the acusticums and the cephalic projection of the lobus vagi. 



Fig. 2j. Roccus. Transection of the oblongata at the exit of the Xth nerve. 



Fig. 24. Amiurus. Transection of the oblongata at the level of the en- 

 trance of IX ? 



Fig. 2J. Catostomus. Transection of the oblongata farther cephalad than 

 figure 22 where the tuberculum impar has been replaced by the fused acusticums. 



Fig. 26. Exoglossum. Transection through the oblongata showing slight 

 overlapping of the tuberculum impar by the lobus vagi and the first appearance 

 of the acusticum. 



PLATE V. 



Ten diagrams to illustrate the regions and nerves discussed which are de- 

 marcated in different colors. 



Figs. 2'j-2g. Diagrams of the sensory (ganglionated) oblongatal nerve 

 roots in Necturus (Amphibia) Ainia and A/niurus. 



Figs, ji, JO, j2, jj. Diagrams of the ohlongatas oi Amia, Perca, A''otemt- 

 gonus and Cyprinus to illustrate the increasing complexity and associated fusions. 

 The left side in Perca and Amia are shown as though the fasciculus communis 

 system were exposed, — as if the covering part of the acusticum had been dis- 

 sected away. (Comp. figs, i and 4.) 



Figs. 34-36. Transections through the oblongata of Amiurus, Amia, and 

 Perca respectively. Fig. 34 caudad of Vlllth ; fig. 35 near the IXtb and fig. 36 

 cephalad of tlie Xth. 



