282 



C. U. Aricns Kappers 



natory reflex-tract oí the optic and vestibular stimuli, the fase. long. 



post. (fig. 14), near which in these animáis also the trochlearis and abdu- 



cens nuclei lie. 



/;/ bouj'-fishcs however (where the nucleus abducens has such an ex- 



tremely ventral position) also the oculomotorius nucleus has, partly at 



least, shifted ventrally as figure 15 shows. The ventral part however is 



not arranged ventro-laterally as is 

 the casewith lampreys, but cióse to 

 the raphe. It is probable that from 

 this part the few crossed root-fibres 



''^r? 



I* 



%L :'/■-> \ ■ -^ ■■■■ 1 



Fig. 14. — Dorsal position of the 

 nucí, oculomotorius, above the 

 fase. long. post. in a .Shark (Sela- 

 che máxima) afler Davidson 

 Black. 



Fig. 15. — División of the nucí, oculo- 

 motorius in a dorso-lateral and ven- 

 tro-medial group, the latter of which 

 reaching to the crossing tr. tecto- 

 bulb. ventr. Gadus morrhua. 



of thís nucleus are proceeding. This ventral nucleus has been effected 

 by and is shifted in the direction of the ventral tecto-bulbar tract from 

 which collaterals are found running to the nucleus. 



So here we meet with an influence analogous to that which is exer- 

 cised by the ventral tecto-bulbar tracts on the abducens nucleus in these 

 animáis (fig. i and 2). 



In higher vertebrates, we ngain find tlie whole of the nucí, oculomo- 

 torius in the immediale neighbourhood of the fase. long. posterior. 



In some Amphibia, its arrangement is still very primitive (Rotliig ?íná 

 Black). In Reptiles it begins to be divided in rather distinct groups, among 

 which a nucleus of Edinger-Westphal or Nucí, accessor.tis III, consisting 



f 



