96 SUPER-ORGANIC EVOLUTION 



investigations of Eetzius and Lenhossek, in the 

 ganglion of the invertebrates. 



" Second Phase. The neuroblastoderm undergoes 

 modification, showing two kinds of expansions, the 

 cylindric axis and some protoplasmic appendices, 

 generally sprung from the initial portion of the 

 latter. This phase, somewhat modified, constitutes 

 the permanent morphology of many medullary and 

 brain corpuscules of fishes and batrachi ; it is 

 characterised, above all, by the absence of basal 

 and lateral protoplasmic expansions of the cellular 

 body. The functional elongation narrows, springing 

 generally from the protoplasmic shoot, and resem- 

 bling a protoplasmic stem differentiated. 



" Third Phase. From the inside of the neuro- 

 blastoderm, as well as on its sides, spring new 

 protoplasmic expansions, which ramify repeatedly. 

 The nervous cell acquires consequently a starred 

 or pyramidal form. The majority of the nervous 

 elements of the encephalus and medulla of birds 

 and mammiferse correspond to this morphological 

 type, which represents the last ontogenic stage of 

 the neuroblastoderm. 



" From this explanation one sees that during the 

 ontogenic development appear forthwith the chief 

 or direct passages (cylindric axes and their free 

 ramification), and later the collateral or indirect 

 passages. In the differentiation of the phylogenic 



