274 



DR. K. KOSTANECKI ON A REMNANT OF THE 



The connection of these folds with the umbilicus furnishes fin 

 immediate explanation of the condition in the adult animal 

 described by Beddard. "Without an}'^ doubt, we have before us a 

 remnant of the involution of the vitelline duct and its blood- 

 vessels, especially its arteries. I have not been able to dissect the 

 precious specimen and make microscopical sections, but examining 

 the strip and its relation to the ileum, I noticed that the wall 

 of the ileum between these folds was smooth ; the vitelline duct 

 had completely disappeared, and blood-vessels were not apparent 

 under the peritoneum forming these folds ; it may be that 

 microscopical sections would ha.ve disclosed degenei'ated remains 

 of the walls of these vessels. In spite of that, there can be no 

 doubt, considering the course of this strip, that it owes its 

 existence to structures connected with the yolk-sac apparatus. 



Text-fieure 1. 



Ceecum and nnilnlicus of Mauatee. 

 6.p.=bitid crecum. 



Especially regarding the symmetrical origin of the two folds 

 from the dorsal mesenterj^ of the terminal portion of the ileum, 

 thei'e can be no doubt that these are produced by the omphalo- 

 mesenteric arteries. The omphalo-mesenteric or vitelline vein 

 or its remains cannot play any part here ; in fcetal life it runs 

 differently, namely, from the umbilicus to the mesoduodenum. 

 In the ftvtus which I have examined it had vanished completely. 



The changes of the omphalo-mesenteric arteries are described 

 by several authors, especially in the very exact paper by 

 Broman*, who, together with the results of previous researches, 

 gives many new data. 



It is known that the omphalo-mesenteric arteries are originally 

 paiied and nin on either side of the ileum to the umbilicus, then 

 unite, both in the part which runs through the mesentery. 



* Broman, " Ubev das Schicksal der Vasa vitellina bei den Saugetieren," Ergebnisse 

 der Anatoniie und Entwickelungsgescbiclitej Bd. xxi. (1913). 



