1883.] NATURAL SCIENCES OF PHILADELPHIA. HT 



PEELIMINARY OBSERVATIONS UPON THE BRAIN OF AMPHIUMA. 

 BY HENRY P. OSBORN, SC. D. 



The North American Urodela, embracing a wide variety of forms 

 which can readily be obtained, offer an attractive field for the 

 comparative study of the amphibian brain. The work upon the 

 subject hitherto has been chiefly in Germany, but many members 

 of this large group have barely been touched upon, so that a sys- 

 tematic research into the whole subject would form a valuable 

 contribution to Comparative Morphology. 



In the hope of extending my study later I have recently been 

 investigating the brain of Amphiuma,^ having procured a quantity 

 of live specimens from New Orleans. This paper contains a pre- 

 liminary account of this investigation. 



Among the more important studies upon the amphibian brain 

 are those of Wy man ,2 Fischer,^ Stieda* and Wilder.^ Stieda's 

 work is principally upon the microscopic structure of the brains 

 of the Frog and Axolotl ; "Wilder, in his study of the Frog and 

 Menobranchus, has directed attention largely to parts of the brain 

 which have been less studied hitherto, namely to the cavities and 

 the thinner portions of the brain parietes surrounding them, as 

 well as to the brain membranes. I am indebted to the writings 

 of both of these authors for light upon this subject, although I 

 have not as yet so fully consulted either as I would like to do. 



In the general description the usual terminology of different 

 portions of the brain is employed, but in referring to the various 

 segments of the brain tube and to the ventricles they enclose I 

 largely employ the terms partly adopted and partly introduced by 

 Wilder. His system of nomenclature, which is chiefly founded 

 upon the embryonic divisions of the brain, is admirably clear and 



^•i employ this title as it is the family name (AmpMumidw), and is more 

 generally known, although Murcenopsis, the three-toed genus, is the one 

 which I studied. 



^ Smithsonian Contributions to Knowledge, Washington, 1853. 



* Amphibiorum Nudorum Neuroglia ; also, Anat, Abhandlungen iiber 

 die Perennibranchiaten und Derotremen. 



* Zeitschrift fiir wiss. Zoologie, Band xx, xxv. 



* Anatomical Technology, Wilder and Gage, 1883, 



