The fine structure of the numerous pores in the median body region of Xiphinema diversicaudatum females was observed by transmission electron microscopy. Each receptor has a characteristic number and arrangement of neurons. Two dendrites with the typical microtubule pattern 9x2, embedded within electron dense material, and representing the sensory system, are present in each receptor and extend into the tip of the pore. The pore contains a channel filled with amorphous material. Each pair of neurons is surrounded by two accessory cells, the socket and the sheath cell. Structural similarities with pores on the anterior part of the body of other phytoparasitic nematodes suggest that each pore represents a chemosensillum and may serve to monitor the environment.