THE CEREBELLUM OF NECTURUS AND OTHER 

 URODELE AMPHIBIA 



C. JUDSON HERRICK 



From the Anatomical Laboratory of the University of Chicago 



THIRTY FIGURES 



The cerebellum of lower urodeles has long been Jcnown to be in 

 a greatly reduced condition; indeed, several authors have stated 

 that in some of these forms it is entirely absent or represented 

 merely by a dorsal commissural band of fibers. The subject 

 obviously presents some features of general morphological inter- 

 est; accordingly, I have examined the cerebellum in such Ameri- 

 can species of Urodela as are readUy available, selecting Necturus 

 maculosus (Raf.) and Amblystoma tigrinum (Green) for more 

 detailed study. The observations on the development and adult 

 structure of the latter t^^pe are reserved for a later report. 



For nearly all of the material upon which this paper is based, 

 including a very extensive series of microscopical preparations and 

 a number of carefully made dissections, I am indebted to the kind- 

 ness of Dr. Paul S. McKibben. 



All of the Amphibia studied possess cerebellar tissue in typical 

 relations and with essentially the same fibrous connections as in 

 other vertebrates, save for the absence of the mammalian brach- 

 ium pontis and its connections. 



The embryological development of the cerebellum of mammals 

 is known to begin as a thickening of the rhomboidal lip along the 

 rostral border of the lateral recess of the fourth ventricle. In 

 adult urodeles the'recessus lateralis is very extensive and in the 

 lower forms the configuration is very similar to that of very early 

 embryonic stages of mammals in that the cerebellar tissue is p^;es- 

 ent only in the walls of the wide lateral recesses, save for a com- 

 missural band of nerve fibers in the brain roof in front of them. 



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THE JOURNAL OF COMPARATIVE NEUROLOGI-, VOL. 24, NO. 1 

 FEBRUARY, 1914 



