551 



Auf das viel erörterte Problem des Homologon des Invertebraten- 

 raundes bei dea Wirbeltieren gehe ich hier nicht ein. Wird einmal 

 die unter 2) forraulirte Uebereinstimmung in den topographischen Be- 

 ziehungen des Blastoporus zugegeben, so ist dieses Problem, wie auch 

 GoETTE anerkennt, nur noch von secundärer Bedeutung. 



Die Gedanken, welche im zweiten Abschnitt dieser Mitteilung 

 skizzirt wurden, lehnen sich eng an Ideen an, welche Hatschek in 

 verschiedenen Arbeiten entwickelt hat, die aber bei den Forschern auf 

 dem Gebiet der Wirbeltierembryologie im Ganzen wenig Beachtung ge- 

 funden zu haben scheinen. 



Phylogenetische Theorien aufzustellen, lag mir fern, ich wollte 

 nur dazu beitragen, einige Fragen möglichst scharf zu formuliren, 

 welche vielleicht Berücksichtigung bei weiteren Untersuchungen ver- 

 dienen. 



Charlottenburg, 5. April 1898. 



Nachdruck verboten. 



An Abnormality in Rana temporaria. 



By Ernest Warren, B. Sc, 

 Demonstrator in Zoology, University College, London W. C. 



With one Figure. 



The accompanying figure represents a very remarkable abnormality 

 which was recently found in a female frog at the Zoological Laboratory 

 University College, London. 



Here there was a vascular connection between the rectal vein of 

 the hepatic portal and the apex of the lung. The blood-vessel was 

 not attached to the mesentery but was quite free in the body-cavity. 

 All the other veins and arteries were apparently normal, the 

 pulmonary vein and artery of the left side were particularly examined 

 but nothing unusual could be detected. Also the anterior abdominal 

 vein was present and so this recto-pulmonary connection cannot be 

 looked upon as a deflection of that blood-vessel. In position it is 

 remotely analogous to the vessel in the Teleostean fish which runs 

 from the rete mirabile of the air-bladder to the portal vein. 



It is very difficult to offer any suggestion as to the origin of 

 this abnormality for it is doubtful whether it can be regarded as a 

 reversion. It is conceivable that it arose pathologically beiog due to 

 some mechanical injury or disease which occurred during embryonic life. 



