12 Journal of Comparative Neurology. 



Elasmobranchs may render easier a close homologization of 

 the regions there. So impressed was Goronowitsch with this 

 relation of the molecular layer of the cerebellum in Acipen- 

 ser that he regarded it as an indication of the primitive integrity 

 of cerebellar and oblongatal regions.^ Whatever may have 

 been the primitive morphologic relations of the cerebellum to 

 the oblongata, the point that should be emphasized, it is felt, is 

 rather the present physiologic relation which must exist between 

 the cerebellum and that, — morphologically most dorsal — part of 

 the oblongata serving as the centre for the nerves of the ear and 

 lateral line organs. Schaper has found that in teleosts as in 

 mammals the fibers of the molecular layer arise by a forking, 

 T-shaped origin of the neurites of the cells of the granular layer. 

 In Amia and many if not all teleosts a large part at least of the 

 fibers of the cerebellar crests of the two sides decussate in the 

 caudal wall of the cerebellum, most clearly seen in Amiiirus. 

 This and other evident connections may better be discussed 

 subsequently. 



At this point very brief mention may be most conveniently 

 made of Lepidostens and Acipenser. A single specimen of the 

 former was available. The resemblance between the oblongata 

 of Amia and Lepidosteiis is very close. As in the former, there 

 is no trace of the so-called lobiis trigeviiiii of Acipenser nor any 

 root to correspond to Tng. II dors, of Goronowitsch. The 

 nerves present in Amia and their components were easily recog- 

 nized, except that, since no Weigert preparations could be 

 made, it was impossible to determine satisfactorily the relations 

 of the spinal Vth tract ; however, it is undoubtedly superficial 

 and much as in Amia. 



The peculiar interest attaching to Acipe^iser (or other stur- 



1 " Die innige Verbindung, welche zwischen Cerebellum und Medulla 

 oblongata bei primitiven Formen nacbzuweisen ist, berechtigt die Ver- 

 muthung, dass wir es hier mit einetn primitiven Character zu thun haben. 

 Es erscheint demnach denkbar, dass das streng von der Oblongata differenzirte 

 Cerebellum der hoheren Wirbelthiere durch allmahliche Reduktion der Cerebel- 

 argebilde der Oblongata und durch eine allmahliche Koncentration dieser 

 Gebilde im differenzirten Hinterhirne der hoheren Wirbelthiere entstehen 

 konnte." etc. Goronowitsch, p. 539. 



