32 Journal of Comparative Neurology. 



appeals to the writer as unsafe, and the opinion expressed be- 

 fore ('95) is adhered to, — that the data for a full comparison of 

 higher and lower forms are insufficient. 



Summary. 



The annexed table may summarize the nerve components 

 of the typical forms examined, and the following points recap- 

 itulate the general results of the study of the oblongata, illus- 

 trated by diagrams of figures 27-36. 



1. Three systems constitute the centers for the ganglion- 

 ated (sensory) nerves of Teleostomes and form the dorsal por- 

 tion of the oblongata : they are, (i) the spinal Vth tract (sys- 

 tem), (2) the fasciculus communis system and (3) the acusticum 

 system. 



2. The first gives fibers to the Vth nerve and in Amia, 

 Amiurus, Perca, Roccus and Lepomis at least, a small contingent 

 to the Xth. 



3. The second furnishes fibers to the VII, and IX and X 

 (visceral and end-bud). 



4. The third furnishes fibers to the VII and IX and X 

 (lateral line system), and gives rise to the Vlllth. 



5. The lobus trigemini and lobus vagi of some Teleosts 

 are but the differentiated pre- and post-auditory portions of the 

 fasciculus communis system. 



6. The "dorsal geniculate root of the Vth" of teleosts 

 is the homologue of Vllaa (Strong) of Amphibia. 



7. The lobus trigemini of Elasmobranchs it is believed 

 will prove more closely related to the acusticum of ganoids and 

 teleosts ; it is clearly the caudal continuation of the restis of 

 the elasmobranch brain. 



8. No secondary fusions of regions were found in Amiurus 

 (Nematognathi) and Esox and Fundulus ( Haplomi). 



9. Fusion of the acusticums occurred in the Acanthopteri 

 (4 families) and in the Isospondyli {Chiped). 



10. Fusion of the acusticums and lobi trigemini is found 

 in the Cyprinidae. 



