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Concerning Rudimentary Teeth in Coregonus wartmanni. 



(Aus dem Anatomischen Institut der Universität Freiburg.) 

 By H. E. Waltee. 



Through the kindness of Prof. Wiedersheim, to whom I am in- 

 debted for the material, and at his suggestion, I have been able to 

 investigate the question of rudimentary teeth in Coregonus wartmanni, 

 the common "Felchen". 



As is wellknown this is the exceptional Salmonoid which is 

 toothless when adult. It is therefore interesting to note that in 

 early embryos up to about 1 cm in length true rudimentary teeth 

 are present in all those regions where teeth normally occur in the 

 other Salnionidse. 



Unfortunately the material at hand was not complete enough to 

 determine how late in development these traces of teeth remain but 

 in the ontogenetically oldest embryos examined they appear already 

 somewhat regenerated from the earlier stages. The earliest stage in 

 which traces of teeth were observed was in embryos not yet hatched. 



The first formation of the teeth seems to be a convoluted in- 

 vagination or infolding of the mouth epithelium, which process results 

 in a superficially lying group of specialized cells. In the most ad- 

 vanced stage of tooth development before regeneration has begun 

 (but not in the most advanced ontogenetic stage observed), the 

 pointed form of the tooth, with its dentine cap, is apparent. 



Later I hope to offer a more detailed and illustrated account of 

 the rudimentary teeth in Coregonus wartmanni in relation to the 

 development of the teeth in allied forms, together with the sugges- 

 tions which these facts give us in regard to the phylogeny of the 

 Salmonidse. 



Freiburg i. B., Easter 1894. 



