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the m-mesenteries, this is especially the case as regards the first 
quartette. The metamesenteries Mi mostly reach almost to the abora 
Figs. 8, 9. Ceriantims (?) mortensenii. 8. Diagram of the arrangement of mesentenes. 
9. The most proximal part of a metamesentery M 2 . 
pole, only in the second specimen (fig. 7) the left Mi-mesentery 
is considerably shorter. The ciliated tract occupies almost the whole 
free edge of the mesentery, in the upper part it is rather straight 
