2« 



new structure, the tuterculua acusticuir-. 



The tubsrculun acustiouni is shown in F'it^s. 1 and ?, t.a. 

 Tt extends posteriorly from the restiformis along the lateral 

 margin of the fourth ventricle some three quarters of the dis- 

 tance to the calamus scrijjtorius, tapering as it proceeds. It 

 is separated from the general cutaneous nucleus below it by a 

 fissure which reches well toward the limitans interna. The 

 outer zone of the acusticum is structurally continuous wit! 

 the cerebellurr,; it is known as the cerebellar crest (Pig.?, 

 cb.cr.). The acusticum is the centre for the nerves of the 

 lateral line sense-organs and the internal ear. Its interpre- 

 tation will be considered in Subsection 7. 



2. Feuie'v of Merve Components . 

 A proper point of view for the structure of the oblonga- 

 ta can best be obtained through familiarity with the problems 

 of the cranial nerves pertaining to this region of the brain. 

 Reference to the text-books of descriptive anatomy will discov- 

 er hardly a trace of the conceptions which dominate the modern 

 morphology of nerves. The discovery made by Sir Charles Bell 

 as to the character of the dorsal and ventral roots of the 

 spinal nerves was one which represented a distinct advance in 

 sound physiology, but the application of Bell's formula to the 

 cranial nerves has not been productive of sound morphology. 

 The effort to compare the cranial with the spinal nerves on the 



