601 



distinct complexes, Oue of these consists of the nerves supplying 

 structures of ectodermal origin, the Vth., Vlllth., and lateral line 

 nerves. The other consists of the nerves which supply structures of 

 entodermal origin, the Vllth., IXth., and Xth. nerves. 



15. The sensory Vth., Vlllth., and lateral line nerves alone are 

 homologous with the sensory roots of the spinal nerves. 



16. The tuberculum acusticum and the cerebellum arc the 

 representatives in the hind brain of the dorsal horns of the cord. 



17. There is in Acipenser a spinal Vlllth. tract which is prob- 

 ably homologous with that in man. 



18. The sensory Vllth., IXth., and Xth. nerves are not homologous 

 with any nerves in the trunk region, 



19. The Lobus vagi has no homologue, or only a rudimentary 

 homologue, in the spinal cord of the adult. 



20. The sensory roots of the cranial nerves can not be considered 

 as serially homologous with (the dorsal roots of) the spinal nerves 

 in determining the segmentation of the brain or head. The motor 

 roots alone are directly comparable to (the ventral roots of) the spinal 

 nerves. 



21. The peculiar character of the Purkinje cell dendrites seems 

 to be due to their physiological relation with the very fine fibres of 

 the molecular layer of the cerebellum. 



Ann Arbor, Michigan, Ü. S. A., May 10, 1898. 



List of papers cited. 

 '89. Allis, The Anatomy and Development of the Lateral Line System 



in Amia calva. Jour. Morph., Vol. 2. 

 '97. AiiLis, The cranial Muscles and cranial and first spinal Nerves in 



Amia calva. Jour. Morph., Vol. 12. 

 '92. Ayers, Vertebrate Cephalogenesis. IL A Contribution to the 



Morphology of the Vertebrate Ear, &c. Jour. Morph., Vol. H. 

 '85. Beard, The System of Branchial Sense Organs and their associated 



Ganglia in Ichthiopsida. A Contribution to the ancestral Histoiy 



of Vertebrates. Q. J. M. S., Vol. 26. 

 '92. BuRCKHAKDT, Das Centralnervensystem von Protopterus annectens. 



Berlin 1892. 

 '96. Cajal, S. Ramon y, Beitrag zum Studium den Medulla oblongata, 



des Kleinhirns und des Ursprungs der Gehirnnerven. Leipzig 1896. 

 '96. CoLE, On the Sensory and Ampullary Canals in Chimaera. Anat. 



Anz., Bd. 12. 

 '89. EwART, On the cranial Nerves of Elasmobranch Fishes. Proc, Roy. 



Soc, Vol. 45. 

 '95. Fish, The central nervous System of Desmognathus fusca. Jour. 



Morph., Vol. 10. 



