328 JouRNAi. OF Comparative Neitroi.ogv. 



velopment of the cranial nerves aims before all to bring its 

 processes into harmony with this hypothesis. 



From no place in his numerous writings does it clearly 

 emerge that he has, in general, seen or noticed the formation 

 of the lateral portion of the principal ganglia from the epi- 

 dermis. In one place(') in his last large publication but one 

 he says, much more explicitly, that the nerves growing out 

 from the border (Leiste) connected themselves at the level 

 of the chorda with the epidermis, which statement points to 

 the epibranchial and not to the principal ganglia. Then, it 

 is said further on, the dorsal branches or supra -branchial 

 nerves arose at the same time xvith the fr(£branchial nerves, 

 along with the separation from the epidermis of the ganglia 

 that arose in the region pointed out — that is, after the origin 

 of the epibranchial ganglia. This expression, also, does not 

 perm.it us to suppose the formation of the dorsal branches 

 connected with the principal ganglia, since the latter arise 

 noticeably earlier than the epibranchial ganglia. 



Also in the last treatis of Beard's, furnished with numer- 

 ous figures, it is said, in accordance with the above-men- 

 tioned expression, that the cranial ganglia corresponding to 

 the spinal ganglia received additional form-elements from 

 the lateral epiblast over the gill clefts and at the height of the 

 chorda. To draw a conclusion from this. Beard might not 

 have seen the formation of the lateral portions of the prin- 

 cipal ganglia, and the lateral ganglia in his and in my sense 

 would not be identical, but Beard's lateral ganglia would 

 correspond to my epibranchial ganglia. Nevertheless, some 

 of his figures show that in the elasmobranchs also the epi- 

 dermis forms ganglia in two well-distinguished series lying 

 apart one over the other, lateral and epibranchial. I refer 

 thereupon to the ^uart. Jour. Mic. Se., Vol. XXVI, 1886, 

 Plate IX, Figs. 20 and 23, on the facialis of Torpedo. Prob- 

 ably the principal and epibranchial ganglia mingle very early 



I Quart. Jour. Mic. Sc, Vol. XXVI, 1886, p. loi. 



