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teniüg out of the relatinship of two sets of vesicles, that have been 

 previously confused, but, the bringing to light of a set of vesicles that 

 has been heretofore overlooked. 



The optic vesicles are now known, through the researches of many 

 investigators, to arise in a large number of animals on the cephalic 

 wall before the brain vesicles are formed. The system of accessory 

 vesicles, described above, are shown, also, to be present before the 

 brain vesicles. This might justify a change in the traditional way of 

 regarding the optic vesicles. Their very first beginning, is customarily 

 spoken of, as a diverticulum from the fore-brain vesicle, but, the facts, 

 would make it appear that this is a secondary rather than a primitive 

 relationship. The optic vesicles are, apparently, the precursors of the 

 brain vesicles. The optic differentiations are older in phylogenetic 

 history than the brain vesicles. The latter have arisen within the 

 vertebrate phylum in connection with the tubular nervous system. 



The main facts of this paper may now be summarized: — There 

 exists in the brain walls of the chick and Acanthias serial differen- 

 tiations of epithelium, that take the form of vesicles, closely connected 

 with the optic vesicles, and therefore called "accessory optic vesicles". 

 These structures are very transitory — extending over a period of three 

 hours in the chick — and they disappear before the true brain ves- 

 icles arise with which they might otherwise become confused. Their 

 existence supports the hypothesis that the vertebrate eyes are seg- 

 mental and that the ancestors of vertebrates were primitively multiple- 

 eyed. In-as-much, the optic vesicles arise before the brain vesicles, 

 the primitive relationship of the former is not that of diverticula from 

 the latter. This condition is secondary. 



Nachdruck verboten. 



Zwei Fälle von dreigliedrigem Daumen. 



Von Dr. Hans Salzer. 



(Aus der 2. medicinischen Abteilung der Krankenanstalt „Rudolfsstiftung" 

 in Wien, Vorstand: Primarius Dr. Eugen Bamberger.) 



Mit 2 Abbildungen. 



Am 30. October stellte Primarius Dr. Bamberger in der K. K. 

 Gesellschaft der Aerzte in Wien einen Fall von .beiderseitigem drei- 

 phalangigem Daumen vor, der von Dr. Pöch mittelst Röntgen- 



