Line drawings of male and female cystacanths of Neoandracantha peruensis from ghost crabs, Ocypode gaudichaudii, from the Pacific Ocean off Peru. 1. Allotype female; note embryonic eggs between foretrunk and midtrunk and developing cephalic ganglion, female reproductive structures, and genital ligaments. 2. A trunk spine from the posterior field of foretrunk spines. 3. The proboscis of paratype female in Figure 1. Note the ventral robust hook no. 14 opposite the normal dorsal hook on the other side; boths hooks are blackened. This is a consistent characteristic of male and female specimens of N. peruensis. 4. The midtrunk of the holotype male showing the characteristic disposition of the diagonal testes. 5. One longitudinal row of selected representative hooks and spines numbered from anterior. 6. The posterior end of the hindtrunk of the male holotype showing the developing bursa and Saefftigen's pouch attached to the posterior end of the genital ligament which runs through the trunk.