The finer Anatomy of the Nervons System 

 of Myxine glutinosa. 



By 

 Dr. John F. Holm 



(Zootomical Institute, Uuiversity (if Stockholm). 



With plates XIX— XXII. 



The anatomy of the brain of Myxine has, during many years, 

 formed a subject for scientific research on account of the low place 

 Myxine takes in the system and its apparent dissimilarity to all 

 other fish brains, those of the Bdellostomae of course excepted. Even 

 the Petromyzontidae, though in many particulars closely related to 

 the Myxinoidae, have a very much higher brain development. Am- 

 phioxus alone, if its place in the system as a true cordate remains 

 undisputed, is the only vertebrate whose brain stands on a lower 

 degree of development and on a stadium wiiich, according to the 

 recent researches of Price (32) and B. Dean (5 and G), may be 

 considered similar to the state of development which exists in very 

 young embryos of Bdellostomae. 



Already as far back as 1S22, Anders Retzius (36) published 

 an account of the surface anatomy of the brain of Myxine and of 

 its peripherical nerves. Some sixteen years later, Johannes Müller 

 (27) in his work »Vergleichende Neurologie der Myxinoidae« gave 

 an excellent account of the centrifugal distribution of the cranial 

 nerves, as well as a description of the macroscopial anatomy. 



Since then W. MCller (28 and 29) has given some details 

 relating to the ventricular system, G. Retzius (38) a modern and 

 complete macroscopical anatomy of the brain and the cranial nerves, 

 as well as a description of the Infundibulum and Hypophysis (39,) 



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