FOSSIL FISH BRAIN 333 



SU:\EMARY • 



Microscopic examination of sections through a nodule contain- 

 ing the brain of a small paleoniscid fish from the Coal ^Measures 

 of Kansas has resulted in the determination of a wide meningeal 

 space, and the possible preservation of the meninges and blood 

 vessels. The meningeal space is filled with vesicular calcite 

 which is readily broken away from the surface of the brain, 

 nerves and ear. 



The brain substance itself is converted into incomplete crj- stals 

 of calcite and phosphate. Since all known brain containing 

 nodules are of about the same nature and substance it will not 

 be possible to discover evidences of microscopic neural struc- 

 tures until brains are found fossilized in a different medium. The 

 fact that the form of the brain was not distorted is explained by 

 the incomplete nature of the minute crystals which replaced its 

 substance. The formation of these crystals has obliterated all 

 traces of organic structure, and only the form of the brain is 

 preserved. This, however, is retained in a beauty which has 

 never been surpassed in fossilized material. 



BIBLIOGRAPHY 



(1) MooDiE, Roy L. 1915 A new fish brain from the Coal Measures of Kansas, 



with a review of other fossil brains. Jour. Comp. Neurol., vol. 25, 

 pp. 13.5-181, 19 figs. 



(2) LiGXiER, O. 1892 LEmploi de la vesuvine dans I'etude de vegetaux fos- 



siles. Bull. Soc. Linneenne de Normandie, 4th ser., Caen, vol. 6, pp. 

 9-10. 



(3) Seitz, Adolf Leo Ludwig 1907 Vergleichenden Studien uber den mikro- 



skopischen knochenbau, etc., Nova Acta Abh. d. Kaiserl. Leop. Carol. 

 Deutsch. Akad. d. Xaturf., Bd. 87, no. 2. 



(4) MooDiE, Roy L. 1920 Concerning the fossilization of blood corpuscles. 



Amer. Naturalist, vol. 54, pp. 460-464, 1 fig. 



THE JOUBXAL OF COMPARATIVE NEUROLOGY, VOL. 32, NO. 3 



