27! 



C. U. Aricns Kappers 



a most curious position, as well with regard to its dorsal as to its sagittal 

 topography. 



The topography in the transversal plañe is clearly shown by figure 8 

 which proves this nucleus in this animal to be situated above the sulcus 

 limitans oí His, at the base oí the cerebellum in which, in higher animáis, 

 still the Crossing of its root is found. 



The sagittal topography of this nucleus is not less singular. 



ton.5em. 



tr. mei 

 cer. 



fase long posf 



Fig. 9. — Position of the trochlearis nucleus underneath the Sulc. limitans, on the 

 fase. long. post. in the eel, after v. d. Horst. 



Accustomed as \ve are by human anatomy to find the nucleus troch- 

 learis directly behind the \. oculomotorius, a large distance in front of 

 the N. trigeminus, \ve find the reverse in the Lamprey, the nucleus IV 

 being located here on a leve! very near to the Vth nucleus. This posi- 

 tion is not so strange since Hqffmaiin ^ found (in Acanthias) that the mus- 

 culus obliquus superior isderived from trigeminus myomere znáBok (l.c), 

 proved the visceral character of this nucleus. 



* Morphol. Jahrbuch, Bnd. 24. 



