Figure 1. Scanning electron micrographs (SEMs) of normal fresh fluke.

a: SEM of the apical cone surface showing smooth oral sucker at its tip, the ventral sucker and the gonopore. OS: oral sucker, VS: ventral sucker, GP: gonopore. b: SEM of the apical cone tegument showing ridged tegument with numerous serrated spines and clusters, fungiform in shape, of sensory papillae surrounding the oral sucker. OS: oral sucker. c: SEM of the ventral sucker showing clusters of sensory papillae (arrows). VS: ventral sucker. d, e: High power SEMs of the spines on the apical cone revealing tightly-packed, posteriorly-directed and broad spines, with a number of finger like protrusions at their tips. There are clusters of sensory papillae scattering throughout the body surface between spines (arrows). S: spine. f: SEM of the mid-body region. Note the spines are not closely-arranged as these on the apical cone. g: SEM of the tail region showing smaller spines (inset) than that covering the rest of the fluke's surface.