The structure of the PC-glycan of the major excretory-secretory product (ES-62) of Acanthocheilonema viteae has been investigated using endoglycosidases and lectins. Results obtained raise the possibility that it may be of the high mannose type. This, and the insensitivity of the PC-glycan to treatments which remove PC or choline from bacterial PC-glycans, suggests that it may be more analogous to fungal, than to bacterial PC-containing glycans.