446 THE XERVOUS SYSTEM. 



This view agrees with that of Yung [179], who compares these 

 structures with the trabecula and corpus fungiforme (' corps en 

 gobelet '), whilst he recognises the complexity of their connec- 

 tions with the rest of the brain. 



The optic peduncle (o) in the Crayfish arises partly from the 

 mesocerebron, although its principal origin appears to be from 

 the thalamic lobe (th). Berger [178] indeed regards the corpus 

 fungiforme as the optic lobe ; and Yung [179] says, ' We re- 

 gard the lateral ganglia (;//, in') as the optic lobes par excel- 

 lence.' From the context it is evident, I think, that he includes 

 the corpus fungiforme as part of the lateral ganglia. Berger 

 held the same opinion. 



Bellonci [183], however, considered the corpus fungiforme as 

 representing the cerebral lobes of the vertebrate an opinion 

 which corresponds with the views of Dujardin [170] and 

 Faivre [171]. 



Rabl-Riickhard* observed that the corpora fungiformia are 

 perfectly normal in the blind ants of the genus Typhlopone, 

 and argues from this that the)' cannot be optic lobes, as Berger 

 supposes. 



My own view is that the corpus fungiforme, or corpora fungi- 

 formia for these organs are usually two in number on each 

 side are not to be regarded as part of the basal ganglia from 

 which the optic nerves are derived, but should rather be con- 

 sidered as similar to the cerebellum of vertebrates, or, to use 

 the nomenclature of Meynert.f as part of the cerebro-cerebellar 

 projection system. 



I shall endeavour to show hereafter that their connections 

 with the rest of the cephalic centres resembles in many points 

 those of cerebellum in vertebrates. 



It is interesting to observe that the optic tract in the Crus- 

 tacea appears to arise mainly from the thalamic lobe; whilst 

 in Insects its connection with the thalamic lobe is less easily 

 seen, and it arises mainly from the mesocerebron. Thus there 



* Rabl-Ruckhard, ' Studien iiber Insectengehirne,' Archiv f. Anat. Physio- 

 logic u. \v. Mcdicin, 1875. p. 488. 



f Sitzungsbericlue d. k. Acad., Wien. iS6Q. 



