58 



ART. 4. — N. YATSÜ : 



liver. The same feature just described is also seen in fresh 

 specimens and in toto preparations, when carefully examined. 



These two mesenteries are probably the remnants of the 

 septa formed in early stages by the apposition of the wall of two 

 cœlomic sacs. 



The ileo-parietal band (PL VI., Figs. 81, 82, PI. VII., 

 Figs. 93, 106, 115, and PI. VIII., Figs. 133, 134, il pr. bel) 

 has a transverse position as is best seen in the accompanying 

 cut, and passes nearly parallel to the frontal plane of the body. 

 Ventrally it becomes narrow and is attached to the ventral body 

 wall near the 31. occlusor posterior. Dorsally it conies to 

 attach itself to the ventral side of the mid-gut. Laterally it is 

 drawn out into two narrow wings : the left wing forms the ventral 



sheath 



right nephridium 



lateral 

 body wall 



ventral 

 body wall 



ileo- 

 parietal 

 band 



attach ment of 



ileoparietal band 



to mid-gut 



M. occlusor 

 posterior 



intestinal 

 mesentery 



intestine 



opening 

 of funnel 



Diagram showing the relations of the ileo-parietal band, the intestinal mesentery, and the 

 nephridia (dorsal view). (The dorsal half of the left nephridium is cut off;. 



