Ultrastructure of the Z organ in Xiphinema ifacolum

Bieve-Zacheo T., Zacheo G. and Lamberti F. 1985. Ultrastructure of the Z organ in Xiphinema ifacolum. International Journal for Parasitology15: 453–461. The uterus in Xiphinema ifacolum can be divided into uterus proper, a 77 μm long tube and a lemon-shaped Z organ, about 28 μm long and 18 μm wide, placed between the oviduct and the uterus proper. The Z organ consists of a thick outer muscular layer of 120 cells, arranged in 20 rings of six cells each and a thin inner epithelium layer, lining the lumen. The epithelial cell walls, lining the lumen of the Z organ are thicker than those lining the uterus proper and are strongly folded. The crests of some of these folds carry six large apophyses, all about the same size and shape, these occupy the full length of the organ, becoming thicker towards the center of the lumen. There are many tubules near the surfaces of the apophyses, the contents of which can be dissolved by treatment with pepsin and pronase, indicating that they are proteins. This material probably consists of secretions which are squeezed out of the apophyses by a passing egg and may function in the formation or hardening of the egg shell.