OMPHALO-MESENTERIC ARTERIES IN THE MANATEE, 273 



19. On a Remnant of the Omphalo-mesenteric Arteries in 

 the Manatee. Bj K. Kostanecki, M.D._, LL.D., 



F.Ac.Sc. Cracow"^. 



[Received February 19, 1923 : Read April 10, 1923.] 

 (Text-figure 1.) 



In a paper published in 1897 in the Proceedings of the Zoological 

 Society (Notes upon the Anatomy of a Manatee, Manatus 

 inunguis), Beddard describes and represents in a drawing the 

 csecum of this animal. The general shape of the caecum is 

 precisely like that of the other species of Manatee, especially of 

 Manatus laiirostris, one specimen of which Beddard has also 

 examined, and which previously had been described by Murief- 

 Beddard adds: "I should not have had the drawing prepared 

 were it not for a peculiar fold of mesentery which it is the main 

 purpose of that sketch to illustrate. This fold, which is not 

 referred to by Dr. Murie, lies on either side of the mesentery 

 supporting the ileum and runs nearl^^to the caecum. It does not 

 bear a blood-vessel, and the fold of either side is continuous 

 with its fellow by a complete bridge over the front side of the 

 ileum as indicated in the sketch. Both species are preciselj^ alike 

 in the presence and in the relations of these two mesenteries." 

 (The drawing in Beddard's paper is also reproduced in Weber's 

 ' Saugetiere.') 



Neither Beddard nor Weber gives an explanation of this, 

 fold. 



I have had the opportunity of examining a Manatee foetus 

 [Manatus inungtiis) 35 cm. in length in the collections of the 

 Royal Museum of Natural History at Brussels, thanks to the 

 kindness of Prof. Dollo. 



The caecum presented the aspect known in the adult animals 

 from the papers of Cuvier, Owen, Home, Murie, Flower, Rapp, 

 Huntington, Beddard, Waldeyer, and others. 



I noticed immediately a few cms. away from the caecum the 

 bilateral folds described by Beddard, which ran from the dorsal 

 mesentery to the wall of the ileum, uniting on its ventral, 

 antimesenteric wall. However, they did not terminate there^ 

 in a narrow bridge, as in Beddard's drav/ing, but the central 

 part was markedly elevated above the surface of the ileum, 

 and was elongated into a narrow strip stretching towards the 

 umbilicus and terminating there (as can be seen in the text- 

 figure, p. 274). 



* Communicated by The Seceetaet. 



t Murie, "On the Form and Structure of the Manatee," Trans. Zool. Soc. viii. 

 p. 127. 



